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§ 1915.1001
Footnotes to Table Z—Shipyards:
1 [Reserved]
2 See Mineral Dusts Table.
3 Use Asbestos Limit § 1915.1001.
4 See 1915.1001.
* The PELs are 8-hour TWAs unless otherwise noted; a (C) designation denotes a ceiling limit. They are to
be determined from breathing-zone air samples.
a Parts of vapor or gas per million parts of contaminated air by volume at 25 °C and 760 torr.
b Milligrams of substance per cubic meter of air. When entry is in this column only, the value is exact; when
listed with a ppm entry, it is approximate.
c [Reserved]
d The CAS number is for information only. Enforcement is based on the substance name. For an entry covering more than one metal compound, measured as the metal, the CAS number for the metal is given—not
CAS numbers for the individual compounds.
e f [Reserved]
g For sectors excluded from § 1915.1028 the limit is 10 ppm TWA.
h Where OSHA has published a proposal for a substance but has not issued a final rule, the proposal is referenced and the existing limit is published.
i [Reserved]
j Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.
k The percentage of crystalline silica in the formula is the amount determined from airborne samples, except
in those instances in which other methods have been shown to be applicable.
m Covers all organic and inorganic particulates not otherwise regulated. Same as Particulates Not Otherwise
Regulated.
n If the exposure limit in § 1915.1026 is stayed or is otherwise not in effect, the exposure limit is a ceiling of
0.1 mg/m3.
o If the exposure limit in § 1915.1026 is stayed or is otherwise not in effect, the exposure limit is 0.1 mg/m3
(as CrO3) as an 8-hour TWA.
The 1970 TLV uses letter designations instead of a numerical value as follows:
A 1 [Reserved]
A 2 Polytetrafluoroethylene decomposition products. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentrations
should be minimal.
A 3 Gasoline and/or Petroleum Distillates. The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable. The content of benzene, other aromatics and
additives should be determined to arrive at the appropriate TLV.
E Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 18% and be within
the requirement addressing explosion in subpart B of part 1915.
[58 FR 35514, July 1, 1993, as amended at 61 FR 56856, Nov. 4, 1996; 62 FR 1619, Jan. 10, 1997;
67 FR 44545, July 3, 2002; 71 FR 10377, Feb. 28, 2006; 71 FR 36009, June 23, 2006; 76 FR 80740, Dec.
27, 2011]
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§ 1915.1001
Asbestos.
(a) Scope and application. This section
regulates asbestos exposure in all shipyard employment work as defined in 29
CFR part 1915, including but not limited to the following:
(1) Demolition or salvage of structures, vessels, and vessel sections
where asbestos is present;
(2) Removal or encapsulation of materials containing asbestos;
(3) Construction, alteration, repair,
maintenance, or renovation of vessels,
vessel sections, structures, substrates,
or portions thereof, that contain asbestos;
(4) Installation of products containing asbestos;
(5) Asbestos spill/emergency cleanup;
and
(6) Transportation, disposal, storage,
containment of and housekeeping activities involving asbestos or products
containing asbestos, on the site or location at which construction activities
are performed.
(7) Coverage under this standard
shall be based on the nature of the
work operation involving asbestos exposure.
(8) This section does not apply to asbestos-containing asphalt roof cements, coatings and mastics.
(b) Definitions. Aggressive method
means removal or disturbance of building/vessel materials by sanding, abrading, grinding, or other method that
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
breaks, crumbles, or otherwise disintegrates intact ACM.
Amended water means water to which
surfactant (wetting agent) has been
added to increase the ability of the liquid to penetrate ACM.
Asbestos includes chrysotile, amosite,
crocidolite,
tremolite
asbestos,
anthophyllite asbestos, actinolite asbestos, and any of these minerals that
has been chemically treated and/or altered. For purposes of this standard,
asbestos includes PACM, as defined
below.
Asbestos-containing material, (ACM)
means any material containing more
than one percent asbestos.
Assistant Secretary means the Assistant Secretary of Labor for Occupational Safety and Health, U.S. Department of Labor, or designee.
Authorized person means any person
authorized by the employer and required by work duties to be present in
regulated areas.
Building/facility/vessel owner is the
legal entity, including a lessee, which
exercises control over management and
record keeping functions relating to a
building, facility, and/or vessel in
which activities covered by this standard take place.
Certified Industrial Hygienist (CIH)
means one certified in the practice of
industrial hygiene by the American
Board of Industrial Hygiene.
Class I asbestos work means activities
involving the removal of thermal system insulation or surfacing ACM/
PACM.
Class II asbestos work means activities
involving the removal of ACM which is
neither TSI or surfacing ACM. This includes, but is not limited to, the removal of asbestos-containing wallboard, floor tile and sheeting, roofing
and siding shingles, and construction
mastics.
Class III asbestos work means repair
and maintenance operations, where
‘‘ACM’’, including TSI and surfacing
ACM and PACM, is likely to be disturbed.
Class IV asbestos work means maintenance and custodial activities during
which employees contact but do not
disturb ACM or PACM and activities to
clean up dust, waste and debris resulting from Class I, II, and III activities.
Clean room means an uncontaminated
room having facilities for the storage
of employees’ street clothing and
uncontaminated materials and equipment.
Closely resemble means that the major
workplace conditions which have contributed to the levels of historic asbestos exposure, are no more protective
than conditions of the current workplace.
Competent person see qualified person.
Critical barrier means one or more
layers of plastic sealed over all openings into a work area or any other
physical barrier sufficient to prevent
airborne asbestos in a work area from
migrating to an adjacent area.
Decontamination area means an enclosed area adjacent and connected to
the regulated area and consisting of an
equipment room, shower area, and
clean room, which is used for the decontamination of workers, materials,
and equipment that are contaminated
with asbestos.
Demolition means the wrecking or
taking out of any load-supporting
structural member and any related
razing, removing, or stripping of asbestos products.
Director means the Director, National
Institute for Occupational Safety and
Health, U.S. Department of Health and
Human Services, or designee.
Disturbance means activities that disrupt the matrix of ACM or PACM,
crumble or pulverize ACM or PACM, or
generate visible debris from ACM or
PACM. Disturbance includes cutting
away small amounts of ACM and
PACM, no greater than the amount
which can be contained in one standard
sized glove bag or waste bag, in order
to access a building or vessel component. In no event shall the amount of
ACM or PACM so disturbed exceed that
which can be contained in one glove
bag or waste bag which shall not exceed 60 inches in length and width.
Employee exposure means that exposure to airborne asbestos that would
occur if the employee were not using
respiratory protective equipment.
Equipment room (change room) means
a contaminated room located within
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Occupational Safety and Health Admin., Labor
the decontamination area that is supplied with impermeable bags or containers for the disposal of contaminated protective clothing and equipment.
Fiber means a particulate form of asbestos, 5 micrometers or longer, with a
length-to-diameter ratio of at least 3 to
1.
Glovebag means not more than a 60×60
inch impervious plastic bag-like enclosure affixed around an asbestos-containing material, with glove-like appendages through which material and
tools may be handled.
High-efficiency particulate air (HEPA)
filter means a filter capable of trapping
and retaining at least 99.97 percent of
all mono-dispersed particles of 0.3 micrometers in diameter.
Homogeneous area means an area of
surfacing material or thermal system
insulation that is uniform in color and
texture.
Industrial hygienist means a professional qualified by education, training,
and experience to anticipate, recognize, evaluate and develop controls for
occupational health hazards.
Intact means that the ACM has not
crumbled, been pulverized, or otherwise
deteriorated so that the asbestos is no
longer likely to be bound with its matrix.
Modification for purposes of paragraph (g)(6)(ii) of this section means a
changed or altered procedure, material
or component of a control system,
which replaces a procedure, material or
component of a required system. Omitting a procedure or component, or reducing or diminishing the stringency
or strength of a material or component
of the control system is not a ‘‘modification’’ for purposes of paragraph
(g)(6) of this section.
Negative Initial Exposure Assessment
means a demonstration by the employer, which complies with the criteria in paragraph (f)(2)(iii) of this section, that employee exposure during an
operation is expected to be consistently below the PELs.
PACM means presumed asbestos containing material.
Presumed asbestos containing material
means thermal system insulation and
surfacing material found in buildings,
vessels, and vessel sections constructed
§ 1915.1001
no later than 1980. The designation of a
material as ‘‘PACM’’ may be rebutted
pursuant to paragraph (k)(5) of this
section.
Project Designer means a person who
has successfully completed the training requirements for an abatement
project designer established by 40
U.S.C. § 763.90(g).
Qualified person means, in addition to
the definition in 29 CFR 1926.32(f), one
who is capable of identifying existing
asbestos hazards in the workplace and
selecting the appropriate control strategy for asbestos exposure, who has the
authority to take prompt corrective
measures to eliminate them, as specified in 29 CFR 1926.32(f); in addition, for
Class I and Class II work who is specially trained in a training course
which meets the criteria of EPA’s
Model Accreditation Plan (40 CFR part
763) for supervisor, or its equivalent,
and for Class III and Class IV work,
who is trained in a manner consistent
with EPA requirements for training of
local education agency maintenance
and custodial staff as set forth at 40
CFR 763.92(a)(2).
Regulated area means an area established by the employer to demarcate
areas where Class I, II, and III asbestos
work is conducted, and any adjoining
area where debris and waste from such
asbestos work accumulate; and a work
area within which airborne concentrations of asbestos, exceed or can reasonably be expected to exceed the permissible exposure limit. Requirements for
regulated areas are set out in paragraph (e) of this section.
Removal means all operations where
ACM and/or PACM is taken out or
stripped from structures or substrates,
and includes demolition operations.
Renovation means the modifying of
any existing vessel, vessel section,
structure, or portion thereof.
Repair means overhauling, rebuilding, reconstructing, or reconditioning
of vessels, vessel sections, structures or
substrates, including encapsulation or
other repair of ACM or PACM attached
to structures or substrates.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
Surfacing material means material
that is sprayed, troweled-on or otherwise applied to surfaces (such as acoustical plaster on ceilings and fireproofing materials on structural members, or other materials on surfaces for
acoustical, fireproofing, and other purposes).
Surfacing ACM means surfacing material which contains more than 1% asbestos.
Thermal system insulation (TSI) means
ACM applied to pipes, fittings, boilers,
breeching, tanks, ducts or other structural components to prevent heat loss
or gain.
Thermal system insulation ACM is
thermal system insulation which contains more than 1% asbestos.
(c) Permissible exposure limits (PELS)—
(1) Time-weighted average limit (TWA).
The employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 0.1
fiber per cubic centimeter of air as an
eight (8) hour time-weighted average
(TWA), as determined by the method
prescribed in appendix A to this section, or by an equivalent method.
(2) Excursion limit. The employer shall
ensure that no employee is exposed to
an airborne concentration of asbestos
in excess of 1.0 fiber per cubic centimeter of air (1 f/cc) as averaged over a
sampling period of thirty (30) minutes,
as determined by the method prescribed in appendix A to this section,
or by an equivalent method.
(d) Multi-employer worksites. (1) On
multi-employer worksites, an employer
performing work requiring the establishment of a regulated area shall inform other employers on the site of the
nature of the employer’s work with asbestos and/or PACM, of the existence of
and requirements pertaining to regulated areas, and the measures taken to
ensure that employees of such other
employers are not exposed to asbestos.
(2) Asbestos hazards at a multi-employer worksite shall be abated by the
contractor who created or controls the
source of asbestos contamination. For
example, if there is a significant
breach of an enclosure containing Class
I work, the employer responsible for
erecting the enclosure shall repair the
breach immediately.
(3) In addition, all employers of employees exposed to asbestos hazards
shall comply with applicable protective
provisions to protect their employees.
For example, if employees working immediately adjacent to a Class I asbestos job are exposed to asbestos due to
the inadequate containment of such
job, their employer shall either remove
the employees from the area until the
enclosure breach is repaired; or perform an initial exposure assessment
pursuant to paragraph (f) of this section.
(4) All employers of employees working adjacent to regulated areas established by another employer on a multiemployer worksite shall take steps on
a daily basis to ascertain the integrity
of the enclosure and/or the effectiveness of the control method relied on by
the primary asbestos contractor to assure that asbestos fibers do not migrate to such adjacent areas.
(5) All general contractors on a shipyard project which includes work covered by this standard shall be deemed
to exercise general supervisory authority over the work covered by this
standard, even though the general contractor is not qualified to serve as the
asbestos ‘‘qualified person’’ as defined
by paragraph (b) of this section. As supervisor of the entire project, the general contractor shall ascertain whether
the asbestos contractor is in compliance with this standard, and shall require such contractor to come into
compliance with this standard when
necessary.
(e) Regulated areas. (1) All Class I, II
and III asbestos work shall be conducted within regulated areas. All
other operations covered by this standard shall be conducted within a regulated area where airborne concentrations of asbestos exceed, or there is a
reasonable possibility they may exceed
a PEL. Regulated areas shall comply
with the requirements of paragraphs
(e) (2), (3), (4) and (5) of this section.
(2) Demarcation. The regulated area
shall be demarcated in any manner
that minimizes the number of persons
within the area and protects persons
outside the area from exposure to airborne asbestos. Where critical barriers
or negative pressure enclosures are
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used, they may demarcate the regulated area. Signs shall be provided and
displayed pursuant to the requirements
of paragraph (k)(7) of this section.
(3) Access. Access to regulated areas
shall be limited to authorized persons
and to persons authorized by the Act or
regulations issued pursuant thereto.
(4) Respirators. All persons entering a
regulated area where employees are required pursuant to paragraph (h)(1) of
this section to wear respirators shall
be supplied with a respirator selected
in accordance with paragraph (h)(2) of
this section.
(5) Prohibited activities. The employer
shall ensure that employees do not eat,
drink, smoke, chew tobacco or gum, or
apply cosmetics in the regulated area.
(6) Qualified persons. The employer
shall ensure that all asbestos work performed within regulated areas is supervised by a qualified person, as defined
in paragraph (b) of this section. The
duties of the qualified person are set
out in paragraph (o) of this section.
(f) Exposure assessments and monitoring—(1) General monitoring criteria. (i)
Each employer who has a workplace or
work operation where exposure monitoring is required under this section
shall perform monitoring to determine
accurately the airborne concentrations
of asbestos to which employees may be
exposed.
(ii) Determinations of employee exposure shall be made from breathing
zone air samples that are representative of the 8-hour TWA and 30-minute
short-term exposures of each employee.
(iii) Representative 8-hour TWA employee exposure shall be determined on
the basis of one or more samples representing full-shift exposure for employees in each work area. Representative 30-minute short-term employee exposures shall be determined on the
basis of one or more samples representing 30 minute exposures associated with operations that are most
likely to produce exposures above the
excursion limit for employees in each
work area.
(2) Initial exposure assessment. (i) Each
employer who has a workplace or work
operation covered by this standard
shall ensure that a ‘‘qualified person’’
conducts an exposure assessment immediately before or at the initiation of
§ 1915.1001
the operation to ascertain expected exposures during that operation or workplace. The assessment must be completed in time to comply with requirements which are triggered by exposure
data or the lack of a ‘‘negative exposure assessment,’’ and to provide information necessary to assure that all
control systems planned are appropriate for that operation and will work
properly.
(ii) Basis of initial exposure assessment.
Unless a negative exposure assessment
has been made pursuant to paragraph
(f)(2)(iii) of this section, the initial exposure assessment shall, if feasible, be
based on monitoring conducted pursuant to paragraph (f)(1)(iii) of this section. The assessment shall take into
consideration both the monitoring results and all observations, information
or calculations which indicate employee exposure to asbestos, including
any previous monitoring conducted in
the workplace, or of the operations of
the employer which indicate the levels
of airborne asbestos likely to be encountered on the job. For Class I asbestos work, until the employer conducts
exposure monitoring and documents
that employees on that job will not be
exposed in excess of the PELs, or otherwise makes a negative exposure assessment
pursuant
to
paragraph
(f)(2)(iii) of this section, the employer
shall presume that employees are exposed in excess of the TWA and excursion limit.
(iii) Negative initial exposure assessment. For any one specific asbestos job
which will be performed by employees
who have been trained in compliance
with the standard, the employer may
demonstrate that employee exposures
will be below the PELs by data which
conform to the following criteria:
(A) Objective data demonstrating
that the product or material containing asbestos minerals or the activity involving such product or material
cannot release airborne fibers in concentrations exceeding the TWA and excursion limit under those work conditions having the greatest potential for
releasing asbestos; or
(B) Where the employer has monitored prior asbestos jobs for the PEL
and the excursion limit within 12
months of the current or projected job,
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
the monitoring and analysis were performed in compliance with the asbestos
standard in effect; and the data were
obtained during work operations conducted under workplace conditions
‘‘closely resembling’’ the processes,
type of material, control methods,
work practices, and environmental
conditions used and prevailing in the
employer’s current operations, the operations were conducted by employees
whose training and experience are no
more extensive than that of employees
performing the current job, and these
data show that under the conditions
prevailing and which will prevail in the
current workplace there is a high degree of certainty that employee exposures will not exceed the TWA and excursion limit; or
(C) The results of initial exposure
monitoring of the current job made
from breathing zone air samples that
are representative of the 8-hour TWA
and 30-minute short-term exposures of
each employee covering operations
which are most likely during the performance of the entire asbestos job to
result in exposures over the PELs.
(3) Periodic monitoring—(i) Class I and
II operations. The employer shall conduct daily monitoring that is representative of the exposure of each employee who is assigned to work within
a regulated area who is performing
Class I or II work, unless the employer
pursuant to paragraph (f)(2)(iii) of this
section, has made a negative exposure
assessment for the entire operation.
(ii) All operations under the standard
other than Class I and II operations. The
employer shall conduct periodic monitoring of all work where exposures are
expected to exceed a PEL, at intervals
sufficient to document the validity of
the exposure prediction.
(iii) Exception. When all employees
required to be monitored daily are
equipped with supplied-air respirators
operated in the pressure demand mode,
or other positive pressure mode respirator, the employer may dispense
with the daily monitoring required by
this paragraph. However, employees
performing Class I work using a control method which is not listed in paragraph (g)(4) (i), (ii), or (iii) of this section or using a modification of a listed
control method, shall continue to be
monitored daily even if they are
equipped with supplied-air respirators.
(4) Termination of monitoring. (i) If the
periodic monitoring required by paragraph (f)(3) of this section reveals that
employee exposures, as indicated by
statistically reliable measurements,
are below the permissible exposure
limit and excursion limit the employer
may discontinue monitoring for those
employees whose exposures are represented by such monitoring.
(ii) Additional monitoring. Notwithstanding the provisions of paragraph (f)
(2) and (3), and (f)(4) of this section, the
employer shall institute the exposure
monitoring required under paragraph
(f)(3) of this section whenever there has
been a change in process, control
equipment, personnel or work practices
that may result in new or additional
exposures above the permissible exposure limit and/or excursion limit or
when the employer has any reason to
suspect that a change may result in
new or additional exposures above the
permissible exposure limit and/or excursion limit. Such additional monitoring is required regardless of whether
a ‘‘negative exposure assessment’’ was
previously produced for a specific job.
(5) Employee notification of monitoring
results. The employer must, as soon as
possible but no later than 5 days after
the receipt of the results of any monitoring performed under this section,
notify each affected employee of these
results either individually in writing or
by posting the results in an appropriate location that is accessible to
employees.
(6) Observation of monitoring. (i) The
employer shall provide affected employees and their designated representatives an opportunity to observe any
monitoring of employee exposure to asbestos conducted in accordance with
this section.
(ii) When observation of the monitoring of employee exposure to asbestos requires entry into an area where
the use of protective clothing or equipment is required, the observer shall be
provided with and be required to use
such clothing and equipment and shall
comply with all other applicable safety
and health procedures.
(g) Methods of compliance—(1) Engineering controls and work practices for all
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Occupational Safety and Health Admin., Labor
operations covered by this section. The
employer shall use the following engineering controls and work practices in
all operations covered by this section,
regardless of the levels of exposure:
(i) Vacuum cleaners equipped with
HEPA filters to collect all debris and
dust containing ACM and PACM, except as provided in paragraph (g)(8)(ii)
of this section in the case of roofing
material;
(ii) Wet methods, or wetting agents,
to control employee exposures during
asbestos handling, mixing, removal,
cutting, application, and cleanup, except where employers demonstrate
that the use of wet methods is infeasible due to for example, the creation of
electrical hazards, equipment malfunction, and, in roofing, except as provided
in paragraph (g)(8)(ii) of this section;
and
(iii) Prompt clean-up and disposal of
wastes and debris contaminated with
asbestos in leak-tight containers except in roofing operations, where the
procedures specified in paragraph
(g)(8)(ii) of this section apply.
(2) In addition to the requirements of
paragraph (g)(1) of this section above,
the employer shall use the following
control methods to achieve compliance
with the TWA permissible exposure
limit and excursion limit prescribed by
paragraph (c) of this section;
(i)
Local
exhaust
ventilation
equipped with HEPA filter dust collection systems;
(ii) Enclosure or isolation of processes producing asbestos dust;
(iii) Ventilation of the regulated area
to move contaminated air away from
the breathing zone of employees and
toward a filtration or collection device
equipped with a HEPA filter;
(iv) Use of other work practices and
engineering controls that the Assistant
Secretary can show to be feasible.
(v) Wherever the feasible engineering
and work practice controls described
above are not sufficient to reduce employee exposure to or below the permissible exposure limit and/or excursion
limit prescribed in paragraph (c) of this
section, the employer shall use them to
reduce employee exposure to the lowest
levels attainable by these controls and
shall supplement them by the use of
respiratory protection that complies
§ 1915.1001
with the requirements of paragraph (h)
of this section.
(3) Prohibitions. The following work
practices and engineering controls
shall not be used for work related to
asbestos or for work which disturbs
ACM or PACM, regardless of measured
levels of asbestos exposure or the results of initial exposure assessments:
(i) High-speed abrasive disc saws that
are not equipped with point of cut ventilator or enclosures with HEPA filtered exhaust air.
(ii) Compressed air used to remove
asbestos, or materials containing asbestos, unless the compressed air is
used in conjunction with an enclosed
ventilation system designed to capture
the dust cloud created by the compressed air.
(iii) Dry sweeping, shoveling or other
dry clean-up of dust and debris containing ACM and PACM.
(iv) Employee rotation as a means of
reducing employee exposure to asbestos.
(4) Class I requirements. In addition to
the provisions of paragraphs (g) (1) and
(2) of this section, the following engineering controls and work practices
and procedures shall be used.
(i) All Class I work, including the installation and operation of the control
system shall be supervised by a qualified person as defined in paragraph (b)
of this section;
(ii) For all Class I jobs involving the
removal of more than 25 linear or 10
square feet of TSI or surfacing ACM or
PACM; for all other Class I jobs, where
the employer cannot produce a negative exposure assessment pursuant to
paragraph (f)(2)(iii) of this section, or
where employees are working in areas
adjacent to the regulated area, while
the Class I work is being performed,
the employer shall use one of the following methods to ensure that airborne
asbestos does not migrate from the regulated area:
(A) Critical barriers shall be placed
over all the openings to the regulated
area, except where activities are performed outdoors; or
(B) The employer shall use another
barrier or isolation method which prevents the migration of airborne asbestos from the regulated area, as verified
by perimeter area surveillance during
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
each work shift at each boundary of
the regulated area, showing no visible
asbestos dust; and perimeter area monitoring showing that clearance levels
contained in 40 CFR part 763, subpart E
of the EPA Asbestos in Schools Rule
are met, or that perimeter area levels,
measured by Phase Contrast Microscopy (PCM) are no more than background levels representing the same
area before the asbestos work began.
The results of such monitoring shall be
made known to the employer no later
than 24 hours from the end of the work
shift represented by such monitoring.
Exception: For work completed outdoors where employees are not working
in areas adjacent to the regulated
areas, this paragraph (g)(4)(ii) is satisfied when the specific control methods
in paragraph (g)(5) of this section are
used.
(iii) For all Class I jobs, HVAC systems shall be isolated in the regulated
area by sealing with a double layer of
6 mil plastic or the equivalent;
(iv) For all Class I jobs, impermeable
dropcloths shall be placed on surfaces
beneath all removal activity;
(v) For all Class I jobs, all objects
within the regulated area shall be covered with impermeable dropcloths or
plastic sheeting which is secured by
duct tape or an equivalent.
(vi) For all Class I jobs where the employer cannot produce a negative exposure assessment or where exposure
monitoring shows the PELs are exceeded, the employer shall ventilate the
regulated area to move contaminated
air away from the breathing zone of
employees toward a HEPA filtration or
collection device.
(5) Specific control systems for Class I
work. In addition, Class I asbestos work
shall be performed using one or more of
the following control methods pursuant to the limitations stated below:
(i) Negative pressure enclosure (NPE)
systems. NPE systems may be used
where the configuration of the work
area does not make the erection of the
enclosure infeasible, with the following
specifications and work practices.
(A) Specifications—(1) The negative
pressure enclosure (NPE) may be of
any configuration,
(2) At least 4 air changes per hour
shall be maintained in the NPE,
(3) A minimum of ¥0.02 column
inches of water pressure differential,
relative to outside pressure, shall be
maintained within the NPE as evidenced by manometric measurements,
(4) The NPE shall be kept under negative pressure throughout the period of
its use, and
(5) Air movement shall be directed
away from employees performing asbestos work within the enclosure, and
toward a HEPA filtration or a collection device.
(B) Work practices—(1) Before beginning work within the enclosure and at
the beginning of each shift, the NPE
shall be inspected for breaches and
smoke-tested for leaks, and any leaks
sealed.
(2) Electrical circuits in the enclosure shall be deactivated, unless
equipped with ground-fault circuit interrupters.
(ii) Glove bag systems may be used to
remove PACM and/or ACM from
straight runs of piping and elbows and
other connections with the following
specifications and work practices:
(A) Specifications—(1) Glovebags shall
be made of 6 mil thick plastic and shall
be seamless at the bottom.
(2) Glovebags used on elbows and
other connections must be designed for
that purpose and used without modifications.
(B) Work practices—(1) Each glovebag
shall be installed so that it completely
covers the circumference of pipes or
other structures where the work is to
be done.
(2) Glovebags shall be smoke-tested
for leaks and any leaks sealed prior to
use.
(3) Glovebags may be used only once
and may not be moved.
(4) Glovebags shall not be used on
surfaces whose temperature exceeds 150
°F.
(5) Prior to disposal, glovebags shall
be collapsed by removing air within
them using a HEPA vacuum.
(6) Before beginning the operation,
loose and friable material adjacent to
the glovebag/box operation shall be
wrapped and sealed in two layers of six
mil plastic or otherwise rendered intact.
(7) Where a system uses an attached
waste bag, such bag shall be connected
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to a collection bag using hose or other
material which shall withstand the
pressure of ACM waste and water without losing its integrity.
(8) A sliding valve or other device
shall separate the waste bag from the
hose to ensure no exposure when the
waste bag is disconnected.
(9) At least two persons shall perform
Class I glovebag removal operations.
(iii) Negative pressure glove bag systems. Negative pressure glove bag systems may be used to remove ACM or
PACM from piping.
(A) Specifications: In addition to the
specifications for glove bag systems
above, negative pressure glove bag systems shall attach the HEPA vacuum
system or other device to the bag to
prevent collapse during removal.
(B) Work practices—(1) The employer
shall comply with the work practices
for glove bag systems in paragraph
(g)(5)(ii)(B)(4) of this section,
(2) The HEPA vacuum cleaner or
other device used to prevent collapse of
bag during removal shall run continually during the operation until it is
completed at which time the bag shall
be collapsed prior to removal of the
bag from the pipe.
(3) Where a separate waste bag is
used along with a collection bag and
discarded after one use, the collection
bag may be reused if rinsed clean with
amended water before reuse.
(iv) Negative pressure glove box systems. Negative pressure glove boxes
may be used to remove ACM or PACM
from pipe runs with the following specifications and work practices.
(A) Specifications—(1) Glove boxes
shall be constructed with rigid sides
and made from metal or other material
which can withstand the weight of the
ACM and PACM and water used during
removal:
(2) A negative pressure generator
shall be used to create negative pressure in the system:
(3) An air filtration unit shall be attached to the box:
(4) The box shall be fitted with gloved
apertures:
(5) An aperture at the base of the box
shall serve as a bagging outlet for
waste ACM and water:
(6) A back-up generator shall be
present on site:
§ 1915.1001
(7) Waste bags shall consist of 6 mil
thick plastic double-bagged before they
are filled or plastic thicker than 6 mil.
(B) Work practices—(1) At least two
persons shall perform the removal:
(2) The box shall be smoke-tested for
leaks and any leaks sealed prior to
each use.
(3) Loose or damaged ACM adjacent
to the box shall be wrapped and sealed
in two layers of 6 mil plastic prior to
the job, or otherwise made intact prior
to the job.
(4) A HEPA filtration system shall be
used to maintain pressure barrier in
box.
(v) Water spray process system. A
water spray process system may be
used for removal of ACM and PACM
from cold line piping if, employees carrying out such process have completed
a 40-hour separate training course in
its use, in addition to training required
for employees performing Class I work.
The system shall meet the following
specifications and shall be performed
by employees using the following work
practices.
(A) Specifications—(1) Piping from
which insulation will be removed shall
be surrounded on 3 sides by rigid framing,
(2) A 360 degree water spray, delivered through nozzles supplied by a high
pressure separate water line, shall be
formed around the piping.
(3) The spray shall collide to form a
fine aerosol which provides a liquid
barrier between workers and the ACM
and PACM.
(B) Work practices—(1) The system
shall be run for at least 10 minutes before removal begins.
(2) All removal shall take place within the barrier.
(3) The system shall be operated by
at least three persons, one of whom
shall not perform removal but shall
check equipment, and ensure proper
operation of the system.
(4) After removal, the ACM and
PACM shall be bagged while still inside
the water barrier.
(vi) A small walk-in enclosure which
accommodates no more than two persons (mini-enclosure) may be used if
the disturbance or removal can be completely contained by the enclosure,
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29 CFR Ch. XVII (7–1–15 Edition)
with the following specifications and
work practices.
(A) Specifications—(1) The fabricated
or job-made enclosure shall be constructed of 6 mil plastic or equivalent:
(2) The enclosure shall be placed
under negative pressure by means of a
HEPA filtered vacuum or similar ventilation unit:
(B) Work practices—(1) Before use, the
mini-enclosure shall be inspected for
leaks and smoketested to detect
breaches, and any breaches sealed.
(2) Before reuse, the interior shall be
completely washed with amended
water and HEPA-vacuumed.
(3) During use, air movement shall be
directed away from the employee’s
breathing zone within the mini-enclosure.
(6) Alternative control methods for Class
I work. Class I work may be performed
using a control method which is not
referenced in paragraph (g)(5) of this
section, or which modifies a control
method referenced in paragraph (g)(5)
of this section, if the following provisions are complied with:
(i) The control method shall enclose,
contain or isolate the processes or
source of airborne asbestos dust, or
otherwise capture or redirect such dust
before it enters the breathing zone of
employees.
(ii) A certified industrial hygienist or
licensed professional engineer who is
also qualified as a project designer as
defined in paragraph (b) of this section,
shall evaluate the work area, the projected work practices and the engineering controls and shall certify in writing that: the planned control method is
adequate to reduce direct and indirect
employee exposure to below the PELs
under worst-case conditions of use, and
that the planned control method will
prevent asbestos contamination outside the regulated area, as measured by
clearance sampling which meets the requirements of EPA’s Asbestos in
Schools Rule issued under AHERA, or
perimeter monitoring which meets the
criteria in paragraph (g)(4)(ii)(B) of
this section.
(A) Where the TSI or surfacing material to be removed is 25 linear or 10
square feet or less , the evaluation required in paragraph (g)(6) of this section may be performed by a ‘‘qualified
person’’, and may omit consideration
of perimeter or clearance monitoring
otherwise required.
(B) The evaluation of employee exposure required in paragraph (g)(6) of this
section, shall include and be based on
sampling and analytical data representing employee exposure during
the use of such method under worstcase conditions and by employees
whose training and experience are
equivalent to employees who are to
perform the current job.
(7) Work practices and engineering controls for Class II work. (i) All Class II
work shall be supervised by a qualified
person as defined in paragraph (b) of
this section.
(ii) For all indoor Class II jobs, where
the employer has not produced a negative exposure assessment pursuant to
paragraph (f)(2)(iii) of this section, or
where during the job, changed conditions indicate there may be exposure
above the PEL or where the employer
does not remove the ACM in a substantially intact state, the employer shall
use one of the following methods to ensure that airborne asbestos does not
migrate from the regulated area;
(A) Critical barriers shall be placed
over all openings to the regulated area;
or,
(B) The employer shall use another
barrier or isolation method which prevents the migration of airborne asbestos from the regulated area, as verified
by perimeter area monitoring or clearance monitoring which meets the criteria set out in paragraph (g)(4)(ii)(B)
of this section.
(C) Impermeable dropcloths shall be
placed on surfaces beneath all removal
activity;
(iii) [Reserved]
(iv) All Class II asbestos work shall
be performed using the work practices
and requirements set out above in
paragraph (g)(1)(i) through (g)(1)(iii) of
this section.
(8) Additional controls for Class II
work. Class II asbestos work shall also
be performed by complying with the
work practices and controls designated
for each type of asbestos work to be
performed, set out in this paragraph.
Where more than one control method
may be used for a type of asbestos
work, the employer may choose one or
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a combination of designated control
methods. Class II work also may be
performed using a method allowed for
Class I work, except that glove bags
and glove boxes are allowed if they
fully enclose the Class II material to be
removed.
(i) For removing vinyl and asphalt
flooring/deck materials which contain
ACM or for which in buildings constructed not later than 1980, the employer has not verified the absence of
ACM pursuant to paragraph (g)(8)(i)(I):
the employer shall ensure that employees comply with the following work
practices and that employees are
trained in these practices pursuant to
paragraph (k)(9) of this section:
(A) Flooring/deck materials or its
backing shall not be sanded.
(B) Vacuums equipped with HEPA filter, disposable dust bag, and metal
floor tool (no brush) shall be used to
clean floors.
(C) Resilient sheeting shall be removed by cutting with wetting of the
snip
point
and
wetting
during
delamination. Rip-up of resilient sheet
floor material is prohibited.
(D) All scraping of residual adhesive
and/or backing shall be performed
using wet methods.
(E) Dry sweeping is prohibited.
(F) Mechanical chipping is prohibited
unless performed in a negative pressure
enclosure which meets the requirements of paragraph (g)(5)(i) of this section.
(G) Tiles shall be removed intact, unless the employer demonstrates that
intact removal is not possible.
(H) When tiles are heated and can be
removed intact, wetting may be omitted.
(I) Resilient flooring/deck material in
buildings/vessels constructed no later
than 1980, including associated mastic
and backing shall be assumed to be asbestos-containing unless an industrial
hygienist determines that it is asbestos-free using recognized analytical
techniques.
(ii) For removing roofing material
which contains ACM the employer
shall ensure that the following work
practices are followed:
(A) Roofing material shall be removed in an intact state to the extent
feasible.
§ 1915.1001
(B) Wet methods shall be used to remove roofing materials that are not intact, or that will be rendered not intact during removal, unless such wet
methods are not feasible or will create
safety hazards.
(C) Cutting machines shall be continuously misted during use, unless a
competent person determines that
misting substantially decreases worker
safety.
(D) When removing built-up roofs
with asbestos-containing roofing felts
and an aggregate surface using a power
roof cutter, all dust resulting from the
cutting operation shall be collected by
a HEPA dust collector, or shall be
HEPA vacuumed by vacuuming along
the cut line. When removing built-up
roofs with asbestos-containing roofing
felts and a smooth surface using a
power roof cutter, the dust resulting
from the cutting operation shall be collected either by a HEPA dust collector
or HEPA vacuuming along the cut line,
or by gently sweeping and then carefully and completely wiping up the
still-wet dust and debris left along the
cut line. The dust and debris shall be
immediately bagged or placed in covered containers.
(E)
Asbestos-containing
material
that has been removed from a roof
shall not be dropped or thrown to the
ground. Unless the material is carried
or passed to the ground by hand, it
shall be lowered to the ground via covered, dust-tight chute, crane or hoist:
(1) Any ACM that is not intact shall
be lowered to the ground as soon as is
practicable, but in any event no later
than the end of the work shift. While
the material remains on the roof it
shall either be kept wet, placed in an
impermeable waste bag, or wrapped in
plastic sheeting.
(2) Intact ACM shall be lowered to
the ground as soon as is practicable,
but in any event no later than the end
of the work shift.
(F) Upon being lowered, unwrapped
material shall be transferred to a
closed receptacle in such manner so as
to preclude the dispersion of dust.
(G) Roof level heating and ventilation air intake sources shall be isolated
or the ventilation system shall be shut
down.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
(H) Notwithstanding any other provision of this section, removal or repair
of sections of intact roofing less than
25 square feet in area does not require
use
of
wet
methods
or
HEPA
vacuuming as long as manual methods
which do not render the material nonintact are used to remove the material
and no visible dust is created by the removal method used. In determining
whether a job involves less than 25
square feet, the employer shall include
all removal and repair work performed
on the same roof on the same day.
(iii) When removing cementitious asbestos-containing siding and shingles
or transite panels containing ACM on
building exteriors (other than roofs,
where paragraph (g)(8)(ii) of this section applies) the employer shall ensure
that the following work practices are
followed:
(A) Cutting, abrading or breaking
siding, shingles, or transite panels
shall be prohibited unless the employer
can demonstrate that methods less
likely to result in asbestos fiber release cannot be used.
(B) Each panel or shingle shall be
sprayed with amended water prior to
removal.
(C) Unwrapped or unbagged panels or
shingles shall be immediately lowered
to the ground via a covered dust-tight
chute, crane or hoist, or be placed in an
impervious waste bag or wrapped in
plastic sheeting and lowered to the
ground no later than the end of the
work shift.
(D) Nails shall be cut with flat, sharp
instruments.
(iv) When removing gaskets containing ACM, the employer shall ensure that the following work practices
are followed:
(A) If a gasket is visibly deteriorated
and unlikely to be removed intact, removal shall be undertaken within a
glovebag as described in paragraph
(g)(5)(ii) of this section.
(B) [Reserved]
(C) The gasket shall be immediately
placed in a disposal container.
(D) Any scraping to remove residue
must be performed wet.
(v) When performing any other Class
II removal of asbestos containing material for which specific controls have
not been listed in paragraph (g)(8)(iv)
(A) through (D) of this section, the employer shall ensure that the following
work practices are complied with.
(A) The material shall be thoroughly
wetted with amended water prior to
and during its removal.
(B) The material shall be removed in
an intact state unless the employer
demonstrates that intact removal is
not possible.
(C) Cutting, abrading or breaking the
material shall be prohibited unless the
employer can demonstrate that methods less likely to result in asbestos
fiber release are not feasible.
(D) Asbestos-containing material removed, shall be immediately bagged or
wrapped, or kept wetted until transferred to a closed receptacle, no later
than the end of the work shift.
(vi) Alternative work practices and controls. Instead of the work practices and
controls listed in paragraphs (g)(8) (i)
through (v) of this section, the employer may use different or modified
engineering and work practice controls
if the following provisions are complied
with.
(A) The employer shall demonstrate
by data representing employee exposure during the use of such method
under conditions which closely resemble the conditions under which the
method is to be used, that employee exposure will not exceed the PELs under
any anticipated circumstances.
(B) A qualified person shall evaluate
the work area, the projected work
practices and the engineering controls,
and shall certify in writing, that the
different or modified controls are adequate to reduce direct and indirect employee exposure to below the PELs
under all expected conditions of use
and that the method meets the requirements of this standard. The evaluation
shall include and be based on data representing employee exposure during
the use of such method under conditions which closely resemble the conditions under which the method is to be
used for the current job, and by employees whose training and experience
are equivalent to employees who are to
perform the current job.
(9) Work practices and engineering controls for Class III asbestos work. Class III
asbestos work shall be conducted using
engineering and work practice controls
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which minimize the exposure to employees performing the asbestos work
and to bystander employees.
(i) The work shall be performed using
wet methods.
(ii) To the extent feasible, the work
shall be performed using local exhaust
ventilation.
(iii) Where the disturbance involves
drilling, cutting, abrading, sanding,
chipping, breaking, or sawing of thermal system insulation or surfacing material, the employer shall use impermeable dropcloths and shall isolate the
operation using mini-enclosures or
glove bag systems pursuant to paragraph (g)(5) of this section or another
isolation method.
(iv) Where the employer does not
demonstrate by a negative exposure assessment performed in compliance with
paragraph (f)(2)(iii) of this section that
the PELs will not be exceeded, or
where
monitoring
results
show
exceedances of a PEL, the employer
shall contain the area using impermeable dropcloths and plastic barriers
or their equivalent, or shall isolate the
operation using mini-enclosure or
glove bag systems pursuant to paragraph (g)(5) of this section.
(v) Employees performing Class III
jobs which involve the disturbance of
TSI or surfacing ACM or PACM or
where the employer does not demonstrate by a ‘‘negative exposure assessment’’ in compliance with paragraph (f)(2)(iii) of this section that the
PELs will not be exceeded or where
monitoring results show exceedances of
the PEL, shall wear respirators which
are selected, used and fitted pursuant
to provisions of paragraph (h) of this
section.
(10) Class IV asbestos work. Class IV
asbestos jobs shall be conducted by employees trained pursuant to the asbestos awareness training program set out
in paragraph (k)(9) of this section. In
addition, all Class IV jobs shall be conducted in conformity with the requirements set out in paragraph (g)(1) of
this section, mandating wet methods,
HEPA vacuums, and prompt clean up
of debris containing ACM or PACM.
(i) Employees cleaning up debris and
waste in a regulated area where respirators are required shall wear respirators which are selected, used and
§ 1915.1001
fitted pursuant to provisions of paragraph (h) of this section.
(ii) Employers of employees cleaning
up waste and debris in an area where
friable TSI or surfacing ACM/PACM is
accessible, shall assume that such
waste and debris contain asbestos.
(11) Specific compliance methods for
brake and clutch repair—(i) Engineering
controls and work practices for brake and
clutch repair and service. During automotive brake and clutch inspection,
disassembly, repair and assembly operations, the employer shall institute engineering controls and work practices
to reduce employee exposure to materials containing asbestos using a negative pressure enclosure/HEPA vacuum
system method or low pressure/wet
cleaning method, which meets the detailed requirements set out in appendix
L to this section. The employer may
also comply using an equivalent method which follows written procedures
which the employer demonstrates can
achieve results equivalent to Method
A. For facilities in which no more than
5 pair of brakes or 5 clutches are inspected, disassembled, repaired, or assembled per week, the method set for
in paragraph [D] of appendix L to this
section may be used.
(ii) The employer may also comply
by using an equivalent method which
follows written procedures, which the
employer demonstrates can achieve
equivalent exposure reductions as do
the two ‘‘preferred methods.’’ Such
demonstration must include monitoring data conducted under workplace
conditions closely resembling the process, type of asbestos containing materials, control method, work practices
and environmental conditions which
the equivalent method will be used, or
objective data, which document that
under all reasonably foreseeable conditions of brake and clutch repair applications, the method results in exposures which are equivalent to the
methods set out in appendix L to this
section.
(12) Alternative methods of compliance
for installation, removal, repair, and
maintenance of certain roofing and pipeline coating materials. Notwithstanding
any other provision of this section, an
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29 CFR Ch. XVII (7–1–15 Edition)
employer who complies with all provisions of this paragraph (g)(12) when installing, removing, repairing, or maintaining intact pipeline asphaltic wrap,
or roof flashings which contain asbestos fibers encapsulated or coated by bituminous or resinous compounds shall
be deemed to be in compliance with
this section. If an employer does not
comply with all provisions of this paragraph (g)(12) or if during the course of
the job the material does not remain
intact, the provisions of paragraph
(g)(8) of this section apply instead of
this paragraph (g)(12).
(i) Before work begins and as needed
during the job, a qualified person who
is capable of identifying asbestos hazards in the workplace and selecting the
appropriate control strategy for asbestos exposure, and who has the authority to take prompt corrective measures
to eliminate such hazards, shall conduct an inspection of the worksite and
determine that the roofing material is
intact and will likely remain intact.
(ii) All employees performing work
covered by this paragraph (g)(12) shall
be trained in a training program that
meets the requirements of paragraph
(k)(9)(viii) of this section.
(iii) The material shall not be sanded, abraded, or ground. Manual methods which do not render the material
non-intact shall be used.
(iv) Material that has been removed
from a roof shall not be dropped or
thrown to the ground. Unless the material is carried or passed to the ground
by hand, it shall be lowered to the
ground via covered, dust-tight chute,
crane or hoist. All such material shall
be removed from the roof as soon as is
practicable, but in any event no later
than the end of the work shift.
(v) Where roofing products which
have been labeled as containing asbestos pursuant to paragraph (k)(8) of this
section are installed on non-residential
roofs during operations covered by this
paragraph (g)(12), the employer shall
notify the building owner of the presence and location of such materials no
later than the end of the job.
(vi) All removal or disturbance of
pipeline asphaltic wrap shall be performed using wet methods.
(h) Respiratory protection—(1) General.
For employees who use respirators re-
quired by this section, the employer
must provide each employee an appropriate respirator that complies with
the requirements of this paragraph.
Respirators must be used in the following circumstances:
(i) During all Class I asbestos jobs.
(ii) During all Class II work where
the ACM is not removed in a substantially intact state.
(iii) During all Class II and III work
which is not performed using wet
methods, provided, however, that respirators need not be worn during removal of ACM from sloped roofs when a
negative exposure assessment has been
made and the ACM is removed in an intact state.
(iv) During all Class II and III asbestos jobs where the employer does not
produce a ‘‘negative exposure assessment.’’
(v) During all Class III jobs where
TSI or surfacing ACM or PACM is
being disturbed.
(vi) During all Class IV work performed within regulated areas where
employees performing other work are
required to wear respirators.
(vii) During all work covered by this
section where employees are exposed
above the TWA or excursion limit.
(viii) In emergencies.
(2) Respirator selection. (i) Employers
must select, and provide to employees
at no cost, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29
CFR 1910.134; however, employers must
not select or use filtering facepiece respirators for use against asbestos fibers.
(ii) Employers are to provide HEPA
filters for powered and non-powered
air-purifying respirators.
(iii) Employers must:
(A) Inform employees that they may
require the employer to provide a
tight-fitting, powered air-purifying respirator (PAPR) permitted for use under
paragraph (h)(2)(i) of this standard instead of a negative pressure respirator.
(B) Provide employees with a tightfitting PAPR instead of a negative
pressure respirator when the employees
choose to use a tight-fitting PAPR and
it provides them with the required protection against asbestos.
(iv) Employers must provide employees with an air-purifying, half mask
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respirator, other than a filtering facepiece respirator, whenever the employees perform:
(A) Class II or Class III asbestos work
for which no negative exposure assessment is available.
(B) Class III asbestos work involving
disturbance of TSI or surfacing ACM or
PACM.
(v) Employers must provide employees with:
(A) A tight-fitting, powered air-purifying respirator or a full facepiece, supplied-air respirator operated in the
pressure-demand mode and equipped
with either HEPA egress cartridges or
an auxiliary positive-pressure, self-contained breathing apparatus (SCBA)
whenever the employees are in a regulated area performing Class I asbestos
work for which a negative exposure assessment is not available and the exposure assessment indicates that the exposure level will be at or below 1 f/cc as
an
8-hour
time-weighted
average
(TWA).
(B) A full facepiece, supplied-air respirator operated in the pressure-demand mode and equipped with an auxiliary positive-pressure SCBA whenever
the employees are in a regulated area
performing Class I asbestos work for
which a negative exposure assessment
is not available and the exposure assessment indicates that the exposure
level will be above 1 f/cc as an 8-hour
TWA.
(3) Respirator program. (i) When respiratory protection is used, the employer shall institute a respiratory protection program in accordance with 29
CFR 1910.134(b) through (d) (except
paragraph (d)(1)(iii)), and (f) through
(m) which covers each employee required by this section to use a respirator.
(ii) No employee shall be assigned to
tasks requiring the use of respirators
if, based on his or her most recent examination, an examining physician determines that the employee will be unable to function normally wearing a
respirator, or that the safety or health
of the employee or of other employees
will be impaired by the use of a respirator. Such employees shall be assigned to another job or given the opportunity to transfer to a different position, the duties of which he or she is
§ 1915.1001
able to perform with the same employer, in the same geographical area,
and with the same seniority, status,
and rate of pay and other job benefits
he or she had just prior to such transfer, if such a different position is available.
(i) Protective clothing—(1) General. The
employer shall provide and require the
use of protective clothing, such as coveralls or similar whole-body clothing,
head coverings, gloves, and foot coverings for any employee exposed to airborne concentrations of asbestos that
exceed the TWA and/or excursion limit
prescribed in paragraph (c) of this section, or for which a required negative
exposure assessment is not produced,
or for any employee performing Class I
operations which involve the removal
of over 25 linear or 10 square feet of TSI
or surfacing ACM or PACM.
(2) Laundering. (i) The employer shall
ensure that laundering of contaminated clothing is done so as to prevent
the release of airborne asbestos in excess of the TWA or excursion limit prescribed in paragraph (c) of this section.
(ii) Any employer who gives contaminated clothing to another person for
laundering shall inform such person of
the requirement in paragraph (i)(2)(i)
of this section to effectively prevent
the release of airborne asbestos in excess of the TWA excursion limit prescribed in paragraph (c) of this section.
(3) The employer shall ensure that
contaminated clothing is transported
in sealed impermeable bags, or other
closed, impermeable containers, and labeled in accordance with paragraph (k)
of this section.
(4) Inspection of protective clothing. (i)
The qualified person shall examine
worksuits worn by employees at least
once per workshift for rips or tears
that may occur during the performance
of work.
(ii) When rips or tears are detected
while an employee is working, rips and
tears shall be immediately mended, or
the worksuit shall be immediately replaced.
(j) Hygiene facilities and practices for
employees. (1) Requirements for employees performing Class I asbestos jobs involving over 25 linear or 10 square feet
of TSI or surfacing ACM and PACM.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
(i) Decontamination areas. For all
Class I jobs involving over 25 linear or
10 square feet of TSI or surfacing ACM
or PACM, the employer shall establish
a decontamination area that is adjacent and connected to the regulated
area for the decontamination of such
employees. The decontamination area
shall consist of an equipment room,
shower area, and clean room in series.
The employer shall ensure that employees enter and exit the regulated
area through the decontamination
area.
(A) Equipment room. The equipment
room shall be supplied with impermeable, labeled bags and containers for
the containment and disposal of contaminated protective equipment.
(B) Shower area. Shower facilities
shall be provided which comply with 29
CFR 1910.141(d)(3), unless the employer
can demonstrate that they are not feasible. The showers shall be adjacent
both to the equipment room and the
clean room, unless the employer can
demonstrate that this location is not
feasible. Where the employer can demonstrate that it is not feasible to locate the shower between the equipment
room and the clean room, or where the
work is performed outdoors, or when
the work involving asbestos exposure
takes place on board a ship, the employers shall ensure that employees:
(1) Remove asbestos contamination
from their worksuits in the equipment
room using a HEPA vacuum before proceeding to a shower that is not adjacent to the work area; or
(2)
Remove
their
contaminated
worksuits in the equipment room, then
don clean worksuits, and proceed to a
shower that is not adjacent to the work
area.
(C) Clean change room. The clean
room shall be equipped with a locker or
appropriate storage container for each
employee’s use. When the employer can
demonstrate that it is not feasible to
provide a clean change area adjacent to
the work area, or where the work is
performed outdoors, or when the work
takes place aboard a ship, the employer
may permit employees engaged in
Class I asbestos jobs to clean their protective clothing with a portable HEPAequipped vacuum before such employees leave the regulated area. Following
showering, such employees however
must then change into street clothing
in clean change areas provided by the
employer which otherwise meet the requirements of this section.
(ii) Decontamination area entry procedures. The employer shall ensure that
employees:
(A) Enter the decontamination area
through the clean room;
(B) Remove and deposit street clothing within a locker provided for their
use; and
(C) Put on protective clothing and
respiratory protection before leaving
the clean room.
(D) Before entering the regulated
area, the employer shall ensure that
employees pass through the equipment
room.
(iii) Decontamination area exit procedures. The employer shall ensure that:
(A) Before leaving the regulated area,
employees shall remove all gross contamination and debris from their protective clothing.
(B) Employees shall remove their
protective clothing in the equipment
room and deposit the clothing in labeled impermeable bags or containers.
(C) Employees shall not remove their
respirators in the equipment room.
(D) Employees shall shower prior to
entering the clean room.
(E) After showering, employees shall
enter the clean room before changing
into street clothes.
(iv) Lunch areas. Whenever food or
beverages are consumed at the worksite where employees are performing
Class I asbestos work, the employer
shall provide lunch areas in which the
airborne concentrations of asbestos are
below the permissible exposure limit
and/or excursion limit.
(2) Requirements for Class I work involving less than 25 linear or 10 square
feet of TSI or surfacing and PACM, and
for Class II and Class III asbestos work
operations where exposures exceed a PEL
or where there is no negative exposure assessment produced before the operation.
(i) The employer shall establish an
equipment room or area that is adjacent to the regulated area for the decontamination of employees and their
equipment which is contaminated with
asbestos which shall consist of an area
covered by an impermeable drop cloth
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Occupational Safety and Health Admin., Labor
on the floor/deck or horizontal working
surface.
(ii) The area must be of sufficient
size as to accommodate cleaning of
equipment and removing personal protective equipment without spreading
contamination beyond the area (as determined by visible accumulations).
(iii) Work clothing must be cleaned
with a HEPA vacuum before it is removed.
(iv) All equipment and surfaces of
containers filled with ACM must be
cleaned prior to removing them from
the equipment room or area.
(v) The employer shall ensure that
employees enter and exit the regulated
area through the equipment room or
area.
(3) Requirements for Class IV work.
Employers shall ensure that employees
performing Class IV work within a regulated area comply with the hygiene
practice required of employees performing work which has a higher classification within that regulated area.
Otherwise employers of employees
cleaning up debris and material which
is TSI or surfacing ACM or identified
as PACM shall provide decontamination facilities for such employees
which are required by paragraph (j)(2)
of this section.
(4) Smoking in work areas. The employer shall ensure that employees do
not smoke in work areas where they
are occupationally exposed to asbestos
because of activities in that work area.
(k) Communication of hazards. (1) This
section applies to the communication
of information concerning asbestos
hazards in shipyard employment activities to facilitate compliance with
this standard. Most asbestos-related
shipyard activities involve previously
installed building materials. Building/
vessel owners often are the only and/or
best sources of information concerning
them. Therefore, they, along with employers of potentially exposed employees, are assigned specific information
conveying and retention duties under
this section. Installed Asbestos Containing Building/Vessel Material: Employers and building/vessel owners
shall identify TSI and sprayed or troweled on surfacing materials as asbestoscontaining unless the employer, by
complying with paragraph (k)(5) of this
§ 1915.1001
section determines that the material is
not asbestos-containing. Asphalt or
vinyl flooring/decking material installed in buildings or vessels no later
than 1980 must also be considered as asbestos containing unless the employer/
owner,
pursuant
to
paragraph
(g)(8)(i)(I) of this section, determines it
is not asbestos containing. If the employer or building/vessel owner has actual knowledge or should have known,
through the exercise of due diligence,
that materials other than TSI and
sprayed-on or troweled-on surfacing
materials are asbestos-containing, they
must be treated as such. When communicating information to employees pursuant to this standard, owners and employers shall identify ‘‘PACM’’ as ACM.
Additional requirements relating to
communication of asbestos work on
multi- employer worksites are set out
in paragraph (d) of this standard.
(2) Duties of building/vessel and facility
owners. (i) Before work subject to this
standard is begun, building/vessel and
facility owners shall determine the
presence, location, and quantity of
ACM and/or PACM at the work site
pursuant to paragraph (k)(1) of this
section.
(ii) Building/vessel and/or facility
owners shall notify the following persons of the presence, location and
quantity of ACM or PACM, at work
sites in their buildings/facilities/vessels. Notification either shall be in
writing or shall consist of a personal
communication between the owner and
the person to whom notification must
be given or their authorized representatives:
(A) Prospective employers applying
or bidding for work whose employees
reasonably can be expected to work in
or adjacent to areas containing such
material;
(B) Employees of the owner who will
work in or adjacent to areas containing
such material:
(C) On multi-employer worksites, all
employers of employees who will be
performing work within or adjacent to
areas containing such materials;
(D) Tenants who will occupy areas
containing such materials.
(3) Duties of employers whose employees
perform work subject to this standard in
or adjacent to areas containing ACM and
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
PACM. Building/vessel and facility
owners whose employees perform such
work shall comply with these provisions to the extent applicable.
(i) Before work in areas containing
ACM and PACM is begun, employers
shall identify the presence, location,
and quantity of ACM, and/or PACM
therein pursuant to paragraph (k)(1) of
this section.
(ii) Before work under this standard
is performed employers of employees
who will perform such work shall inform the following persons of the location and quantity of ACM and/or PACM
present at the worksite and the precautions to be taken to ensure that airborne asbestos is confined to the area.
(iii) Within 10 days of the completion
of such work, the employer whose employees have performed work subject to
this standard, shall inform the building/vessel or facility owner and employers of employees who will be working in the area of the current location
and quantity of PACM and/or ACM remaining in the former regulated area
and final monitoring results, if any.
(4) In addition to the above requirements, all employers who discover
ACM and/or PACM on a work site shall
convey information concerning the
presence, location and quantity of such
newly discovered ACM and/or PACM to
the owner and to other employers of
employees working at the work site,
within 24 hours of the discovery.
(5) Criteria to rebut the designation
of installed material as PACM. (i) At
any time, an employer and/or building/
vessel owner may demonstrate, for purposes of this standard, that PACM does
not contain asbestos. Building/vessel
owners and/or employers are not required to communicate information
about the presence of building material
for which such a demonstration pursuant to the requirements of paragraph
(k)(5)(ii) of this section has been made.
However, in all such cases, the information, data and analysis supporting
the determination that PACM does not
contain asbestos, shall be retained pursuant to paragraph (n) of this section.
(ii) An employer or owner may demonstrate that PACM does not contain
more than 1% asbestos by the following:
(A) Having completed an inspection
conducted pursuant to the requirements of AHERA (40 CFR part 763, subpart E) which demonstrates that the
material is not ACM; or
(B) Performing tests of the material
containing PACM which demonstrate
that no ACM is present in the material.
Such tests shall include analysis of
bulk samples collected in the manner
described in 40 CFR 763.86. The tests,
evaluation and sample collection shall
be conducted by an accredited inspector or by a CIH. Analysis of samples
shall be performed by persons or laboratories
with
proficiency
demonstrated by current successful participation in a nationally recognized testing program such as the National Voluntary Laboratory Accreditation Program (NVLAP) or the National Institute for Standards and Technology
(NIST) or the Round Robin for bulk
samples administered by the American
Industrial Hygiene Association (AIHA),
or an equivalent nationally-recognized
round robin testing program.
(iii) The employer and/or building/
vessel owner may demonstrate that
flooring material including associated
mastic and backing does not contain
asbestos, by a determination of an industrial hygienist based upon recognized analytical techniques showing
that the material is not ACM.
(6) At the entrance to mechanical
rooms/areas in which employees reasonably can be expected to enter and
which contain ACM and/or PACM, the
building/vessel owner shall post signs
which identify the material which is
present, its location, and appropriate
work practices which, if followed, will
ensure that ACM and/or PACM will not
be disturbed. The employer shall ensure, to the extent feasible, that employees who come in contact with
these signs can comprehend them.
Means to ensure employee comprehension may include the use of foreign languages, pictographs, graphics, and
awareness training.
(7) Hazard communication. (i) Labels
shall be affixed to all products containing asbestos and to all containers
containing such products, including
waste containers. Where feasible, installed asbestos products shall contain
a visible label.
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Occupational Safety and Health Admin., Labor
(ii) General. The employer shall include asbestos in the program established to comply with the Hazard Communication
Standard
(HCS)
(§ 1910.1200). The employer shall ensure
that each employee has access to labels
on containers of asbestos and safety
data sheets, and is trained in accordance with the provisions of the HCS
and paragraph (k)(9) of this section.
The employer shall ensure that at least
the following hazards are addressed:
Cancer and lung effects.
(iii) Labels. (A) The employer shall
ensure that labels of bags or containers
of protective clothing and equipment,
scrap, waste, and debris containing asbestos fibers bear the following information:
DANGER
CONTAINS ASBESTOS FIBERS
MAY CAUSE CANCER
CAUSES DAMAGE TO LUNGS
DO NOT BREATHE DUST
AVOID CREATING DUST
provided and displayed at each location
where a regulated area is required to be
established by paragraph (e) of this section. Signs shall be posted at such a
distance from such a location that an
employee may read the signs and take
necessary protective steps before entering the area marked by the signs.
(ii) The warning signs required by
this paragraph (k)(8) shall bear the following legend:
DANGER
ASBESTOS
MAY CAUSE CANCER
CAUSES DAMAGE TO LUNGS
AUTHORIZED PERSONNEL ONLY
(iii) In addition, where the use of respirators and protective clothing is required in the regulated area under this
section, the warning signs shall include
the following:
WEAR RESPIRATORY PROTECTION
AND PROTECTIVE CLOTHING IN THIS
AREA
(B)(1) Prior to June 1, 2015, employers
may include the following information
on raw materials, mixtures or labels of
bags or containers of protective clothing and equipment, scrap, waste, and
debris containing asbestos fibers in lieu
of the labeling requirements in paragraphs (k)(7)(ii) and (k)(7)(iii)(A) of this
section:
DANGER
CONTAINS ASBESTOS FIBERS
AVOID CREATING DUST
CANCER AND LUNG DISEASE HAZARD
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§ 1915.1001
(2) Labels shall also contain a warning statement against breathing asbestos fibers.
(iv) The provisions for labels required
in paragraph (k)(7) of this section do
not apply where:
(A) Asbestos fibers have been modified by a bonding agent, coating, binder, or other material, provided that the
manufacturer can demonstrate that,
during any reasonably foreseeable use,
handling, storage, disposal, processing,
or transportation, no airborne concentrations of asbestos fibers in excess
of the permissible exposure limit and/
or excursion limit will be released, or
(B) Asbestos is present in a product
in concentrations less than 1.0 percent.
(8) Signs. (i) Warning signs that demarcate the regulated area shall be
(iv) The employer shall ensure that
employees working in and contiguous
to regulated areas comprehend the
warning signs required to be posted by
paragraph (k)(8) of this section. Means
to ensure employee comprehension
may include the use of foreign languages, pictographs, and graphics.
(v) When a building/vessel owner or
employer identifies previously installed PACM and/or ACM, labels or
signs shall be affixed or posted so that
employees will be notified of what materials contain PACM and/or ACM. The
employer shall attach such labels in
areas where they will clearly be noticed by employees who are likely to be
exposed, such as at the entrance to mechanical room/areas. Signs required by
paragraph (k)(6) of this section may be
posted in lieu of labels, so long as they
contain information required for labeling. The employer shall ensure, to the
extent feasible, that employees who
come in contact with these signs or labels can comprehend them. Means to
ensure employee comprehension may
include the use of foreign languages,
pictographs, graphics, and awareness
training.
(vi) Prior to June 1, 2016, employers
may use the following legend in lieu of
that specified in paragraph (k)(8)(ii) of
this section:
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
DANGER
ASBESTOS
CANCER AND LUNG DISEASE HAZARD
AUTHORIZED PERSONNEL ONLY
(vii) Prior to June 1, 2016, employers
may use the following legend in lieu of
that specified in paragraph (k)(8)(iii) of
this section:
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RESPIRATORS AND PROTECTIVE CLOTHING ARE REQUIRED IN THIS AREA
(9) Employee information and training.
(i) The employer shall train each employee who is likely to be exposed in
excess of a PEL and each employee who
performs Class I through IV asbestos
operations in accordance with the requirements of this section. Training
shall be provided at no cost to the employee. The employer shall institute a
training program and ensure employee
participation in the program.
(ii) Training shall be provided prior
to or at the time of initial assignment
and at least annually thereafter.
(iii) Training for Class I operations
and for Class II operations that require
the use of critical barriers (or equivalent isolation methods) and/or negative
pressure enclosures under this section
shall be the equivalent in curriculum,
training method and length to the EPA
Model Accreditation Plan (MAP) asbestos abatement workers training (40
CFR part 763, subpart E, appendix C).
(iv) Training for other Class II work.
(A) For work with asbestos containing roofing materials, flooring materials, siding materials, ceiling tiles,
or transite panels, training shall include at a minimum all the elements
included in paragraph (k)(9)(viii) of
this section and in addition, the specific work practices and engineering
controls set forth in paragraph (g) of
this section which specifically relate to
that category. Such course shall include ‘‘hands-on’’ training and shall
take at least 8 hours.
(B) An employee who works with
more than one of the categories of material
specified
in
paragraph
(k)(9)(iv)(A) of this section shall receive training in the work practices applicable to each category of material
that the employee removes and each
removal method that the employee
uses.
(C) For Class II operations not involving the categories of material spec-
ified in paragraph (k)(9)(iv)(A) of this
section, training shall be provided
which shall include at a minimum all
the elements included in paragraph
(k)(9)(viii) of this section and in addition, the specific work practices and
engineering controls set forth in paragraph (g) of this section which specifically relate to the category of material
being removed, and shall include
‘‘hands-on’’ training in the work practices applicable to each category of
material that the employee removes
and each removal method that the employee uses.
(v) Training for Class III employees
shall be consistent with EPA requirements for training of local education
agency maintenance and custodial staff
as set forth at 40 CFR 763.92(a)(2). Such
a course shall also include ‘‘hands-on’’
training and shall take at least 16
hours. Exception: For Class III operations for which the competent person
determines that the EPA curriculum
does not adequately cover the training
needed to perform that activity, training shall include as a minimum all the
elements
included
in
paragraph
(k)(9)(viii) of this section and in addition, the specific work practices and
engineering controls set forth in paragraph (g) of this section which specifically relate to that activity, and shall
include ‘‘hands-on’’ training in the
work practices applicable to each category of material that the employee
disturbs.
(vi) Training for employees performing Class IV operations shall be
consistent with EPA requirements for
training of local education agency
maintenance and custodial staff as set
forth at 40 CFR 763.92(a)(1). Such a
course shall include available information concerning the locations of thermal system insulation and surfacing
ACM/PACM, and asbestos-containing
flooring material, or flooring material
where the absence of asbestos has not
yet been certified; and instruction in
the recognition of damage, deterioration, and delamination of asbestos containing building materials. Such a
course shall take at least 2 hours.
(vii) Training for employees who are
likely to be exposed in excess of the
PEL and who are not otherwise required to be trained under paragraph
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Occupational Safety and Health Admin., Labor
(k)(9) (iii) through (vi) of this section,
shall meet the requirements of paragraph (k)(9)(viii) of this section.
(viii) The training program shall be
conducted in a manner that the employee is able to understand. In addition to the content required by the provisions in paragraphs (k)(9)(iii) through
(vi) of this section, the employer shall
ensure that each such employee is informed of the following:
(A) Methods of recognizing asbestos,
including the requirement in paragraph
(k)(1) of this section to presume that
certain building materials contain asbestos;
(B) The health effects associated with
asbestos exposure;
(C) The relationship between smoking and asbestos in producing lung cancer;
(D) The nature of operations that
could result in exposure to asbestos,
the importance of necessary protective
controls to minimize exposure including, as applicable, engineering controls, work practices, respirators,
housekeeping procedures, hygiene facilities, protective clothing, decontamination procedures, emergency procedures, and waste disposal procedures,
and any necessary instruction in the
use of these controls and procedures;
where Class III and IV work will be or
is performed, the contents of EPA 20T–
2003, ‘‘Managing Asbestos In-Place’’
July 1990 or its equivalent in content;
(E) The purpose, proper use, fitting
instructions, and limitations of respirators as required by 29 CFR 1910.134;
(F) The appropriate work practices
for performing the asbestos job;
(G) Medical surveillance program requirements;
(H) The content of this standard including appendices;
(I) The names, addresses and phone
numbers of public health organizations
which provide information, materials
and/or conduct programs concerning
smoking cessation. The employer may
distribute the list of such organizations contained in appendix J to this
section, to comply with this requirement; and
(J) The requirements for posting
signs and affixing labels and the meaning of the required legends for such
signs and labels.
§ 1915.1001
(10) Access to training materials. (i)
The employer shall make readily available to affected employees without
cost, written materials relating to the
employee training program, including
a copy of this regulation.
(ii) The employer shall provide to the
Assistant Secretary and the Director,
upon request, all information and
training materials relating to the employee information and training program.
(iii) The employer shall inform all
employees concerning the availability
of self-help smoking cessation program
material. Upon employee request, the
employer shall distribute such material, consisting of NIH Publication No,
89–1647, or equivalent self-help material, which is approved or published by
a public health organization listed in
appendix J to this section.
(l)
Housekeeping—(1)
Vacuuming.
Where vacuuming methods are selected, HEPA filtered vacuuming
equipment must be used. The equipment shall be used and emptied in a
manner that minimizes the reentry of
asbestos into the workplace.
(2) Waste disposal. Asbestos waste,
scrap, debris, bags, containers, equipment, and contaminated clothing consigned for disposal shall be collected
and disposed of in sealed, labeled, impermeable bags or other closed, labeled, impermeable containers except
in roofing operations, where the procedures specified in paragraph (g)(8)(ii) of
this section apply.
(3) Care of asbestos-containing flooring/
deck material. (i) All vinyl and asphalt
flooring/deck material shall be maintained in accordance with this paragraph unless the building/facility
owner demonstrates, pursuant to paragraph (g)(8)(i)(I) of this section that the
flooring/deck does not contain asbestos.
(ii) Sanding of flooring/deck material
is prohibited.
(iii) Stripping of finishes shall be
conducted using low abrasion pads at
speeds lower than 300 rpm and wet
methods.
(iv) Burnishing or dry buffing may be
performed only on flooring/deck which
has sufficient finish so that the pad
cannot contact the flooring/deck material.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
(4) Waste and debris and accompanying dust in an area containing accessible thermal system insulation or
surfacing ACM/PACM or visibly deteriorated ACM:
(i) Shall not be dusted or swept dry,
or vacuumed without using a HEPA filter;
(ii) Shall be promptly cleaned up and
disposed of in leak tight containers.
(m) Medical surveillance—(1) General—
(i) Employees covered. (A) The employer
shall institute a medical surveillance
program for all employees who for a
combined total of 30 or more days per
year are engaged in Class I, II and III
work or are exposed at or above a permissible exposure limit. For purposes
of this paragraph, any day in which a
worker engages in Class II or Class III
operations or a combination thereof on
intact material for one hour or less
(taking into account the entire time
spent on the removal operation, including cleanup) and, while doing so, adheres fully to the work practices specified in this standard, shall not be
counted.
(B) For employees otherwise required
by this standard to wear a negative
pressure respirator, employers shall ensure employees are physically able to
perform the work and use the equipment. This determination shall be
made under the supervision of a physician.
(ii) Examination. (A) The employer
shall ensure that all medical examinations and procedures are performed by
or under the supervision of a licensed
physician, and are provided at no cost
to the employee and at a reasonable
time and place.
(B) Persons other than such licensed
physicians who administer the pulmonary function testing required by
this section shall complete a training
course in spirometry sponsored by an
appropriate academic or professional
institution.
(2) Medical examinations and consultations—(i) Frequency. The employer shall
make available medical examinations
and consultations to each employee
covered under paragraph (m)(1)(i) of
this section on the following schedules:
(A) Prior to assignment of the employee to an area where negative-pressure respirators are worn;
(B) When the employee is assigned to
an area where exposure to asbestos
may be at or above the permissible exposure limit for 30 or more days per
year, or engage in Class I, II, or III
work for a combined total of 30 or more
days per year, a medical examination
must be given within 10 working days
following the thirtieth day of exposure;
(C) And at least annually thereafter.
(D) If the examining physician determines that any of the examinations
should be provided more frequently
than specified, the employer shall provide such examinations to affected employees at the frequencies specified by
the physician.
(E) Exception: No medical examination is required of any employee if adequate records show that the employee
has been examined in accordance with
this paragraph within the past 1-year
period.
(ii) Content. Medical examinations
made available pursuant to paragraphs
(m)(2)(i) (A) through (m)(2)(i) (C) of this
section shall include:
(A) A medical and work history with
special emphasis directed to the pulmonary, cardiovascular, and gastrointestinal systems.
(B) On initial examination, the
standardized questionnaire contained
in part 1 of appendix D to this section
and, on annual examination, the abbreviated standardized questionnaire contained in part 2 of appendix D to this
section.
(C) A physical examination directed
to the pulmonary and gastrointestinal
systems, including a chest x-ray to be
administered at the discretion of the
physician, and pulmonary function
tests of forced vital capacity (FVC) and
forced expiratory volume at one second
(FEV(1)). Interpretation and classification of chest roentgenogram shall be
conducted in accordance with appendix
E to this section.
(D) Any other examinations or tests
deemed necessary by the examining
physician.
(3) Information provided to the physician. The employer shall provide the
following information to the examining physician:
(i) A copy of this standard and appendices D, E, and I to this section;
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Occupational Safety and Health Admin., Labor
(ii) A description of the affected employee’s duties as they relate to the
employee’s exposure;
(iii) The employee’s representative
exposure level or anticipated exposure
level;
(iv) A description of any personal
protective and respiratory equipment
used or to be used; and
(v) Information from previous medical examinations of the affected employee that is not otherwise available
to the examining physician.
(4) Physician’s written opinion. (i) The
employer shall obtain a written opinion from the examining physician. This
written opinion shall contain the results of the medical examination and
shall include:
(A) The physician’s opinion as to
whether the employee has any detected
medical conditions that would place
the employee at an increased risk of
material health impairment from exposure to asbestos;
(B) Any recommended limitations on
the employee or on the use of personal
protective equipment such as respirators; and
(C) A statement that the employee
has been informed by the physician of
the results of the medical examination
and of any medical conditions that
may result from asbestos exposure.
(D) A statement that the employee
has been informed by the physician of
the increased risk of lung cancer attributable to the combined effect of
smoking and asbestos exposure.
(ii) The employer shall instruct the
physician not to reveal in the written
opinion given to the employer specific
findings or diagnoses unrelated to occupational exposure to asbestos.
(iii) The employer shall provide a
copy of the physician’s written opinion
to the affected employee within 30 days
from its receipt.
(n) Recordkeeping—(1) Objective data
relied on pursuant to paragraph (f) of this
section. (i) Where the employer has relied on objective data that demonstrates that products made from or
containing asbestos or the activity involving such products or material are
not capable of releasing fibers of asbestos in concentrations at or above the
permissible exposure limit and/or excursion limit under the expected condi-
§ 1915.1001
tions of processing, use, or handling to
satisfy the requirements of paragraph
(f) of this section, the employer shall
establish and maintain an accurate
record of objective data reasonably relied upon in support of the exemption.
(ii) The record shall include at least
the following information:
(A) The product qualifying for exemption;
(B) The source of the objective data;
(C) The testing protocol, results of
testing, and/or analysis of the material
for the release of asbestos;
(D) A description of the operation exempted and how the data support the
exemption; and
(E) Other data relevant to the operations, materials, processing, or employee exposures covered by the exemption.
(iii) The employer shall maintain
this record for the duration of the employer’s reliance upon such objective
data.
(2) Exposure measurements. (i) The employer shall keep an accurate record of
all measurements taken to monitor
employee exposure to asbestos as prescribed in paragraph (f) of this section.
Note: The employer may utilize the
services of qualified organizations such
as industry trade associations and employee associations to maintain the
records required by this section.
(ii) This record shall include at least
the following information:
(A) The date of measurement;
(B) The operation involving exposure
to asbestos that is being monitored;
(C) Sampling and analytical methods
used and evidence of their accuracy;
(D) Number, duration, and results of
samples taken;
(E) Type of protective devices worn,
if any; and
(F) Name, social security number,
and exposure of the employees whose
exposures are represented.
(iii) The employer shall maintain
this record for at least thirty (30)
years, in accordance with 29 CFR
1910.1020.
(3) Medical surveillance. (i) The employer shall establish and maintain an
accurate record for each employee subject to medical surveillance by paragraph (m) of this section, in accordance
with 29 CFR 1910.1020.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
(ii) The record shall include at least
the following information:
(A) The name and social security
number of the employee;
(B) A copy of the employee’s medical
examination results, including the
medical history, questionnaire responses, results of any tests, and physician’s recommendations.
(C) Physician’s written opinions;
(D) Any employee medical complaints related to exposure to asbestos;
and
(E) A copy of the information provided to the physician as required by
paragraph (m) of this section.
(iii) The employer shall ensure that
this record is maintained for the duration of employment plus thirty (30)
years, in accordance with 29 CFR
1910.1020.
(4) Training records. The employer
shall maintain all employee training
records for one (1) year beyond the last
date of employment by that employer.
(5) Data to rebut PACM. (i) Where the
building owner and employer have relied on data to demonstrate that PACM
is not asbestos-containing, such data
shall be maintained for as long as they
are relied upon to rebut the presumption.
(ii) [Reserved]
(6) Records of required notification. (i)
Where the building/vessel owner has
communicated and received information concerning the identity, location
and quantity of ACM and PACM, written records of such notifications and
their content shall be maintained by
the owner for the duration of ownership and shall be transferred to successive owners of such buildings/facilities/
vessels.
(ii) [Reserved]
(7) Availability. (i) The employer,
upon written request, shall make all
records required to be maintained by
this section available to the Assistant
Secretary and the Director for examination and copying.
(ii) The employer, upon request, shall
make any exposure records required by
paragraphs (f) and (n) of this section
available for examination and copying
to affected employees, former employees, designated representatives, and
the Assistant Secretary, in accordance
with 29 CFR 1910.1020(a) through (e) and
(g) through (i).
(iii) The employer, upon request,
shall make employee medical records
required by paragraphs (m) and (n) of
this section available for examination
and copying to the subject employee,
anyone having the specific written consent of the subject employee, and the
Assistant Secretary, in accordance
with 29 CFR 1910.1020.
(8) Transfer of records. The employer
shall comply with the requirements
concerning transfer of records set forth
in 29 CFR 1910.1020(h).
(o) Qualified person—(1) General. On
all shipyard worksites covered by this
standard, the employer shall designate
a qualified person, having the qualifications and authority for ensuring
worker safety and health required by
subpart C, General Safety and Health
Provisions for Construction (29 CFR
1926.20 through 1926.32).
(2) Required inspections by the qualified
person. § 1926.20(b)(2) which requires
health and safety prevention programs
to provide for frequent and regular inspections of the job sites, materials,
and equipment to be made by qualified
persons, is incorporated.
(3) Additional inspections. In addition,
the qualified person shall make frequent and regular inspections of the
job sites, in order to perform the duties
set out in paragraph (o)(3)(i) of this
section. For Class I jobs, on-site inspections shall be made at least once during each work shift, and at any time at
employee request. For Class II, III and
IV jobs, on-site inspections shall be
made at intervals sufficient to assess
whether conditions have changed, and
at any reasonable time at employee request.
(i) On all worksites where employees
are engaged in Class I or II asbestos
work, the qualified person designated
in accordance with paragraph (e)(6) of
this section shall perform or supervise
the following duties, as applicable:
(A) Set up the regulated area, enclosure, or other containment;
(B) Ensure (by on-site inspection) the
integrity of the enclosure or containment;
(C) Set up procedures to control
entry to and exit from the enclosure
and/or area;
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Occupational Safety and Health Admin., Labor
(D) Supervise all employee exposure
monitoring required by this section
and ensure that it is conducted as required by paragraph (f) of this section;
(E) Ensure that employees working
within the enclosure and/or using glove
bags wear respirators and protective
clothing as required by paragraphs (h)
and (i) of this section;
(F) Ensure through on-site supervision, that employees set up, use, and
remove engineering controls, use work
practices and personal protective
equipment in compliance with all requirements;
(G) Ensure that employees use the
hygiene facilities and observe the decontamination procedures specified in
paragraph (j) of this section;
(H) Ensure that through on-site inspection, engineering controls are functioning properly and employees are
using proper work practices; and
(I) Ensure that notification requirements in paragraph (k) of this section
are met.
(4) Training for the competent person.
(i) For Class I and II asbestos work the
qualified person shall be trained in all
aspects of asbestos removal and handling, including: Abatement, installation, removal and handling; the contents of this standard; the identification of asbestos; removal procedures,
where appropriate; and other practices
for reducing the hazard. Such training
shall be obtained in a comprehensive
course for supervisors, that meets the
criteria of EPA’s Model Accreditation
Plan (40 CFR part 763, subpart E, appendix C), such as a course conducted
by an EPA-approved or state-approved
training provider, certified by EPA or a
state, or a course equivalent in stringency, content, and length.
(ii) For Class III and IV asbestos
work, the qualified person shall be
trained in aspects of asbestos handling
appropriate for the nature of the work,
to include procedures for setting up
glove bags and mini-enclosures, practices for reducing asbestos exposures,
use of wet methods, the contents of
this standard, and the identification of
asbestos. Such training shall include
successful completion of a course that
is consistent with EPA requirements
for training of local education agency
maintenance and custodial staff as set
§ 1915.1001
forth at 40 CFR 763.92(a)(2), or its
equivalent in stringency, content, and
length. Qualified persons for Class III
and Class IV work may also be trained
pursuant to the requirements of paragraph (o)(4)(i) of this section.
(p) Appendices. (1) Appendices A, C, D,
and E to this section are incorporated
as part of this section and the contents
of these appendices are mandatory.
(2) Appendices B, F, H, I, J, and K to
this section are informational and are
not intended to create any additional
obligations not otherwise imposed or
to detract from any existing obligations.
APPENDIX A TO § 1915.1001—OSHA REFERENCE
METHOD (MANDATORY)
This mandatory appendix specifies the procedure for analyzing air samples for asbestos, and specifies quality control procedures
that must be implemented by laboratories
performing the analysis. The sampling and
analytical methods described below represent the elements of the available monitoring methods (such as appendix B to this
section, the most current version of the
OSHA method ID–160, or the most current
version of the NIOSH Method 7400) which
OSHA considers to be essential to achieve
adequate employee exposure monitoring
while allowing employers to use methods
that are already established within their organizations. All employers who are required
to conduct air monitoring under paragraph
(f) of this section are required to utilize analytical laboratories that use this procedure,
or an equivalent method, for collecting and
analyzing samples.
Sampling and Analytical Procedure
1. The sampling medium for air samples
shall be mixed cellulose ester filter membranes. These shall be designated by the
manufacturer as suitable for asbestos counting. See below for rejection of blanks.
2. The preferred collection device shall be
the 25-mm diameter cassette with an openfaced 50-mm extension cowl. The 37-mm cassette may be used if necessary but only if
written justification for the need to use the
37-mm filter cassette accompanies the sample results in the employee’s exposure monitoring record. Other cassettes such as the
Bell-mouth may be used within the limits of
their validation. Do not reuse or reload cassettes for asbestos sample collection.
3. An air flow rate between 0.5 liter/min
and 5 liters/min shall be selected for the 25mm cassette. If the 37-mm cassette is used,
an air flow rate between 1 liter/min and 5 liters/min shall be selected.
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31
§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
4. Where possible, a sufficient air volume
for each air sample shall be collected to
yield between 100 and 1,300 fibers per square
millimeter on the membrane filter. If a filter
darkens in appearance or if loose dust is seen
on the filter, a second sample shall be started.
5. Ship the samples in a rigid container
with sufficient packing material to prevent
dislodging the collected fibers. Packing material that has a high electrostatic charge on
its surface (e.g., expanded polystyrene) cannot be used because such material can cause
loss of fibers to the sides of the cassette.
6. Calibrate each personal sampling pump
before and after use with a representative filter cassette installed between the pump and
the calibration devices.
7. Personal samples shall be taken in the
‘‘breathing zone’’ of the employee (i.e., attached to or near the collar or lapel near the
worker’s face).
8. Fiber counts shall be made by positive
phase contrast using a microscope with an 8
to 10 X eyepiece and a 40 to 45 X objective for
a total magnification of approximately 400 X
and a numerical aperture of 0.65 to 0.75. The
microscope shall also be fitted with a green
or blue filter.
9. The microscope shall be fitted with a
Walton-Beckett eyepiece graticule calibrated for a field diameter of 100 micrometers (±2 micrometers).
10. The phase-shift detection limit of the
microscope shall be about 3 degrees measured using the HSE phase shift test slide as
outlined below.
a. Place the test slide on the microscope
stage and center it under the phase objective.
b. Bring the blocks of grooved lines into
focus.
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NOTE: The slide consists of seven sets of
grooved lines (ca. 20 grooves to each block)
in descending order of visibility from sets 1
to 7, seven being the least visible. The requirements
for
asbestos,
tremolite,
anthophyllite, and actinolite counting are
that the microscope optics must resolve the
grooved lines in set 3 completely, although
they may appear somewhat faint, and that
the grooved lines in sets 6 and 7 must be invisible. Sets 4 and 5 must be at least partially visible but may vary slightly in visibility between microscopes. A microscope
that fails to meet these requirements has either too low or too high a resolution to be
used for asbestos, tremolite, anthophyllite,
and actinolite counting.
c. If the image deteriorates, clean and adjust the microscope optics. If the problem
persists, consult the microscope manufacturer.
11. Each set of samples taken will include
10% field blanks or a minimum of 2 field
blanks. These blanks must come from the
same lot as the filters used for sample collection. The field blank results shall be averaged and subtracted from the analytical results before reporting. A set consists of any
sample or group of samples for which an
evaluation for this standard must be made.
Any samples represented by a field blank
having a fiber count in excess of the detection limit of the method being used shall be
rejected.
12. The samples shall be mounted by the
acetone/triacetin method or a method with
an equivalent index of refraction and similar
clarity.
13. Observe the following counting rules.
a. Count only fibers equal to or longer than
5 micrometers. Measure the length of curved
fibers along the curve.
b. In the absence of other information,
count all particles as asbestos that have a
length-to-width ratio (aspect ratio) of 3 to 1
or greater.
c. Fibers lying entirely within the boundary of the Walton-Beckett graticule field
shall receive a count of 1. Fibers crossing the
boundary once, having one end within the
circle, shall receive the count of one half
(1⁄2). Do not count any fiber that crosses the
graticule boundary more than once. Reject
and do not count any other fibers even
though they may be visible outside the graticule area.
d. Count bundles of fibers as one fiber unless individual fibers can be identified by observing both ends of an individual fiber.
e. Count enough graticule fields to yield
100 fibers. Count a minimum of 20 fields; stop
counting at 100 fields regardless of fiber
count.
14. Blind recounts shall be conducted at
the rate of 10 percent.
Quality Control Procedures
1. Intra-laboratory program. Each laboratory and/or each company with more than
one microscopist counting slides shall establish a statistically designed quality assurance program involving blind recounts and
comparisons between microscopists to monitor the variability of counting by each
microscopist and between microscopists. In a
company with more than one laboratory, the
program shall include all laboratories and
shall also evaluate the laboratory-to-laboratory variability.
2. a. Interlaboratory program. Each laboratory
analyzing
asbestos,
tremolite,
anthophyllite, and actinolite samples for
compliance determination shall implement
an interlaboratory quality assurance program that as a minimum includes participation of at least two other independent laboratories. Each laboratory shall participate
in round robin testing at least once every 6
months with at least all the other laboratories in its interlaboratory quality assurance group. Each laboratory shall submit
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Occupational Safety and Health Admin., Labor
slides typical of its own work load for use in
this program. The round robin shall be designed and results analyzed using appropriate statistical methodology.
b. All laboratories should participate in a
national sample testing scheme such as the
Proficiency Analytical Testing Program
(PAT), the Asbestos Registry sponsored by
the American Industrial Hygiene Association
(AIHA).
3. All individuals performing asbestos,
tremolite, anthophyllite, and actinolite
analysis must have taken the NIOSH course
for sampling and evaluating airborne asbes-
§ 1915.1001
tos, tremolite, anthophyllite, and actinolite
dust or an equivalent course.
4. When the use of different microscopes
contributes to differences between counters
and laboratories, the effect of the different
microscope shall be evaluated and the microscope shall be replaced, as necessary.
5. Current results of these quality assurance programs shall be posted in each laboratory to keep the microscopists informed.
APPENDIX B TO § 1915.1001—DETAILED PROCEDURES FOR ASBESTOS SAMPLING AND ANALYSIS (NON-MANDATORY)
Matrix:
Air
OSHA Permissible Exposure Limits:
Time Weighted Average ......................................................................................... 0.1 fiber/cc
Excursion Level (30 minutes) ................................................................................. 1.0 fiber/cc
Collection Procedure:
A known volume of air is drawn through a 25-mm diameter cassette containing a mixed-cellulose ester filter.
The cassette must be equipped with an electrically conductive 50-mm extension cowl. The sampling time
and rate are chosen to give a fiber density of between 100 to 1,300 fibers/mm2 on the filter.
Recommended Sampling Rate ............................................................................................. 0.5 to 5.0 liters/
minute (L/min)
Recommended Air Volumes:
Minimum ................................................................................................................. 25 L
Maximum ................................................................................................................ 2,400 L
Analytical Procedure: A portion of the
sample filter is cleared and prepared for asbestos fiber counting by Phase Contrast Microscopy (PCM) at 400X.
Commercial manufacturers and products
mentioned in this method are for descriptive
use only and do not constitute endorsements
by USDOL-OSHA. Similar products from
other sources can be substituted.
1. Introduction
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This method describes the collection of
airborne asbestos fibers using calibrated
sampling pumps with mixed-cellulose ester
(MCE) filters and analysis by phase contrast
microscopy (PCM). Some terms used are
unique to this method and are defined below:
Asbestos: A term for naturally occurring fibrous minerals. Asbestos includes chrysotile,
crocidolite,
amosite
(cummingtonitegrunerite asbestos), tremolite asbestos, actinolite asbestos, anthophyllite asbestos, and
any of these minerals that have been chemically treated and/or altered. The precise
chemical formulation of each species will
vary with the location from which it was
mined. Nominal compositions are listed:
Chrysotile ......
Crocidolite .....
Amosite .........
Tremolite-actinolite.
Anthophyllite
Mg3Si2O5(OH)4
Na2Fe32+Fe23+Si8O22(OH)2
(Mg,Fe)7Si8O22(OH)2
Ca2(Mg,Fe)5Si8O22(OH)2
(Mg,Fe)7Si8O22(OH)2
Asbestos Fiber: A fiber of asbestos which
meets the criteria specified below for a fiber.
Aspect Ratio: The ratio of the length of a
fiber to it’s diameter (e.g. 3:1, 5:1 aspect ratios).
Cleavage Fragments: Mineral particles
formed by comminution of minerals, especially those characterized by parallel sides
and a moderate aspect ratio (usually less
than 20:1).
Detection Limit: The number of fibers necessary to be 95% certain that the result is
greater than zero.
Differential Counting: The term applied to
the practice of excluding certain kinds of fibers from the fiber count because they do
not appear to be asbestos.
Fiber: A particle that is 5 μm or longer,
with a length-to-width ratio of 3 to 1 or
longer.
Field: The area within the graticule circle
that is superimposed on the microscope
image.
Set: The samples which are taken, submitted to the laboratory, analyzed, and for
which, interim or final result reports are
generated.
Tremolite, Anthophyllite, and Actinolite: The
non-asbestos form of these minerals which
meet the definition of a fiber. It includes any
of these minerals that have been chemically
treated and/or altered.
Walton-Beckett Graticule: An eyepiece graticule specifically designed for asbestos fiber
counting. It consists of a circle with a projected diameter of 100 ±2 μm (area of about
0.00785 mm2) with a crosshair having ticmarks at 3-μm intervals in one direction and
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
5-μm in the orthogonal direction. There are
marks around the periphery of the circle to
demonstrate the proper sizes and shapes of
fibers. This design is reproduced in figure 1.
The disk is placed in one of the microscope
eyepieces so that the design is superimposed
on the field of view.
1.1. History
1.4. Workplace Exposure
Early surveys to determine asbestos exposures were conducted using impinger counts
of total dust with the counts expressed as
million particles per cubic foot. The British
Asbestos Research Council recommended filter membrane counting in 1969. In July 1969,
the Bureau of Occupational Safety and
Health published a filter membrane method
for counting asbestos fibers in the United
States. This method was refined by NIOSH
and published as P & CAM 239. On May 29,
1971, OSHA specified filter membrane sampling with phase contrast counting for evaluation of asbestos exposures at work sites in
the United States. The use of this technique
was again required by OSHA in 1986. Phase
contrast microscopy has continued to be the
method of choice for the measurement of occupational exposure to asbestos.
Asbestos is used by the construction industry in such products as shingles, floor tiles,
asbestos cement, roofing felts, insulation
and acoustical products. Non-construction
uses include brakes, clutch facings, paper,
paints, plastics, and fabrics. One of the most
significant exposures in the workplace is the
removal and encapsulation of asbestos in
schools, public buildings, and homes. Many
workers have the potential to be exposed to
asbestos during these operations.
About 95% of the asbestos in commercial
use in the United States is chrysotile. Crocidolite and amosite make up most of the remainder. Anthophyllite and tremolite or actinolite are likely to be encountered as contaminants in various industrial products.
1.2. Principle
Air is drawn through a MCE filter to capture airborne asbestos fibers. A wedge shaped
portion of the filter is removed, placed on a
glass microscope slide and made transparent.
A measured area (field) is viewed by PCM.
All the fibers meeting defined criteria for asbestos are counted and considered a measure
of the airborne asbestos concentration.
1.3. Advantages and Disadvantages
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copy techniques. A further disadvantage of
PCM is that the smallest visible fibers are
about 0.2 μm in diameter while the finest asbestos fibers may be as small as 0.02 μm in
diameter. For some exposures, substantially
more fibers may be present than are actually
counted.
There are four main advantages of PCM
over other methods:
(1) The technique is specific for fibers.
Phase contrast is a fiber counting technique
which excludes non-fibrous particles from
the analysis.
(2) The technique is inexpensive and does
not require specialized knowledge to carry
out the analysis for total fiber counts.
(3) The analysis is quick and can be performed on-site for rapid determination of air
concentrations of asbestos fibers.
(4) The technique has continuity with historical epidemiological studies so that estimates of expected disease can be inferred
from long-term determinations of asbestos
exposures.
The main disadvantage of PCM is that it
does not positively identify asbestos fibers.
Other fibers which are not asbestos may be
included in the count unless differential
counting is performed. This requires a great
deal of experience to adequately differentiate asbestos from non-asbestos fibers. Positive identification of asbestos must be performed by polarized light or electron micros-
1.5. Physical Properties
Asbestos fiber possesses a high tensile
strength along its axis, is chemically inert,
non-combustible, and heat resistant. It has a
high electrical resistance and good sound absorbing properties. It can be weaved into cables, fabrics or other textiles, and also matted into asbestos papers, felts, or mats.
2. Range and Detection Limit
2.1. The ideal counting range on the filter
is 100 to 1,300 fibers/mm2. With a WaltonBeckett graticule this range is equivalent to
0.8 to 10 fibers/field. Using NIOSH counting
statistics, a count of 0.8 fibers/field would
give an approximate coefficient of variation
(CV) of 0.13.
2.2. The detection limit for this method is
4.0 fibers per 100 fields or 5.5 fibers/mm2. This
was determined using an equation to estimate the maximum CV possible at a specific
concentration (95% confidence) and a Lower
Control Limit of zero. The CV value was
then used to determine a corresponding concentration from historical CV vs fiber relationships. As an example:
Lower Control Limit (95% Confidence) =
AC—1.645(CV)(AC)
Where:
AC = Estimate of the airborne fiber concentration (fibers/cc) Setting the Lower
Control Limit = 0 and solving for CV:
0 = AC—1.645(CV)(AC)
CV = 0.61
This value was compared with CV vs. count
curves. The count at which CV = 0.61 for
Leidel-Busch counting statistics (8.9.) or for
an OSHA Salt Lake Technical Center
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Occupational Safety and Health Admin., Labor
(OSHA-SLTC) CV curve (see appendix A for
further information) was 4.4 fibers or 3.9 fibers per 100 fields, respectively. Although a
lower detection limit of 4 fibers per 100 fields
is supported by the OSHA-SLTC data, both
data sets support the 4.5 fibers per 100 fields
value.
3. Method Performance—Precision and
Accuracy
Precision is dependent upon the total number of fibers counted and the uniformity of
the fiber distribution on the filter. A general
rule is to count at least 20 and not more than
100 fields. The count is discontinued when 100
fibers are counted, provided that 20 fields
have already been counted. Counting more
than 100 fibers results in only a small gain in
precision. As the total count drops below 10
fibers, an accelerated loss of precision is
noted.
At this time, there is no known method to
determine the absolute accuracy of the asbestos analysis. Results of samples prepared
through the Proficiency Analytical Testing
(PAT) Program and analyzed by the OSHASLTC showed no significant bias when compared to PAT reference values. The PAT
samples were analyzed from 1987 to 1989
(N=36) and the concentration range was from
120 to 1,300 fibers/mm2.
4. Interferences
Fibrous substances, if present, may interfere with asbestos analysis.
Some common fibers are:
fiberglass
anhydrate
plant fibers
perlite veins
gypsum
some synthetic fibers
membrane structures
sponge spicules
diatoms
microorganism
wollastonite
The use of electron microscopy or optical
tests such as polarized light, and dispersion
staining may be used to differentiate these
materials from asbestos when necessary.
5. Sampling
lpowell on DSK54DXVN1OFR with $$_JOB
5.1. Equipment
5.1.1. Sample assembly (The assembly is
shown in figure 3). Conductive filter holder
consisting of a 25-mm diameter, 3-piece cassette having a 50-mm long electrically conductive extension cowl. Backup pad, 25-mm,
cellulose. Membrane filter, mixed-cellulose
ester (MCE), 25-mm, plain, white, 0.4 to 1.2μm pore size.
NOTES: (a) DO NOT RE-USE CASSETTES.
§ 1915.1001
(b) Fully conductive cassettes are required
to reduce fiber loss to the sides of the cassette due to electrostatic attraction.
(c) Purchase filters which have been selected by the manufacturer for asbestos
counting or analyze representative filters for
fiber background before use. Discard the filter lot if more than 4 fibers/100 fields are
found.
(d) To decrease the possibility of contamination, the sampling system (filter-backup
pad-cassette)
for
asbestos
is
usually
preassembled by the manufacturer.
(e) Other cassettes, such as the Bellmouth, may be used within the limits of
their validation.
5.1.2. Gel bands for sealing cassettes.
5.1.3. Sampling pump.
Each pump must be a battery operated,
self-contained unit small enough to be
placed on the monitored employee and not
interfere with the work being performed. The
pump must be capable of sampling at the collection rate for the required sampling time.
5.1.4. Flexible tubing, 6-mm bore.
5.1.5. Pump calibration.
Stopwatch and bubble tube/burette or electronic meter.
5.2. Sampling Procedure
5.2.1. Seal the point where the base and
cowl of each cassette meet with a gel band or
tape.
5.2.2. Charge the pumps completely before
beginning.
5.2.3. Connect each pump to a calibration
cassette with an appropriate length of 6-mm
bore plastic tubing. Do not use luer connectors—the type of cassette specified above has
built-in adapters.
5.2.4. Select an appropriate flow rate for
the situation being monitored. The sampling
flow rate must be between 0.5 and 5.0 L/min
for personal sampling and is commonly set
between 1 and 2 L/min. Always choose a flow
rate that will not produce overloaded filters.
5.2.5. Calibrate each sampling pump before
and after sampling with a calibration cassette in-line (Note: This calibration cassette
should be from the same lot of cassettes used
for sampling). Use a primary standard (e.g.
bubble burette) to calibrate each pump. If
possible, calibrate at the sampling site.
NOTE: If sampling site calibration is not
possible, environmental influences may affect the flow rate. The extent is dependent
on the type of pump used. Consult with the
pump manufacturer to determine dependence
on environmental influences. If the pump is
affected by temperature and pressure
changes, correct the flow rate by using the
formula shown in the section ‘‘Sampling
Pump Flow Rate Corrections’’ at the end of
this appendix.
5.2.6. Connect each pump to the base of
each sampling cassette with flexible tubing.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
Remove the end cap of each cassette and
take each air sample open face. Assure that
each sample cassette is held open side down
in the employee’s breathing zone during
sampling. The distance from the nose/mouth
of the employee to the cassette should be
about 10 cm. Secure the cassette on the collar or lapel of the employee using spring
clips or other similar devices.
5.2.7. A suggested minimum air volume
when sampling to determine TWA compliance is 25 L. For Excursion Limit (30 min
sampling time) evaluations, a minimum air
volume of 48 L is recommended.
5.2.8. The most significant problem when
sampling for asbestos is overloading the filter with non-asbestos dust. Suggested maximum air sample volumes for specific environments are:
Environment
Air vol. (L)
lpowell on DSK54DXVN1OFR with $$_JOB
Asbestos removal operations (visible dust) .......
Asbestos removal operations (little dust) ...........
Office environments ...........................................
end-to-end. Also wrap tape around the cassette at each joint to keep the seal secure.
5.3. Sample Shipment
5.3.1. Send the samples to the laboratory
with paperwork requesting asbestos analysis.
List any known fibrous interferences present
during sampling on the paperwork. Also,
note the workplace operation(s) sampled.
5.3.2. Secure and handle the samples in
such that they will not rattle during shipment nor be exposed to static electricity. Do
not ship samples in expanded polystyrene
peanuts, vermiculite, paper shreds, or excelsior. Tape sample cassettes to sheet bubbles
and place in a container that will cushion
the samples in such a manner that they will
not rattle.
5.3.3. To avoid the possibility of sample
contamination, always ship bulk samples in
separate mailing containers.
100
240
400 to
2,400
6. Analysis
6.1. Safety Precautions
Caution: Do not overload the filter with
dust. High levels of non-fibrous dust particles may obscure fibers on the filter and
lower the count or make counting impossible. If more than about 25 to 30% of the
field area is obscured with dust, the result
may be biased low. Smaller air volumes may
be necessary when there is excessive non-asbestos dust in the air.
While sampling, observe the filter with a
small flashlight. If there is a visible layer of
dust on the filter, stop sampling, remove and
seal the cassette, and replace with a new
sampling assembly. The total dust loading
should not exceed 1 mg.
5.2.9. Blank samples are used to determine
if any contamination has occurred during
sample handling. Prepare two blanks for the
first 1 to 20 samples. For sets containing
greater than 20 samples, prepare blanks as
10% of the samples. Handle blank samples in
the same manner as air samples with one exception: Do not draw any air through the
blank samples. Open the blank cassette in
the place where the sample cassettes are
mounted on the employee. Hold it open for
about 30 seconds. Close and seal the cassette
appropriately. Store blanks for shipment
with the sample cassettes.
5.2.10. Immediately after sampling, close
and seal each cassette with the base and
plastic plugs. Do not touch or puncture the
filter membrane as this will invalidate the
analysis.
5.2.11 Attach and secure a sample seal
around each sample cassette in such a way
as to assure that the end cap and base plugs
cannot be removed without destroying the
seal. Tape the ends of the seal together since
the seal is not long enough to be wrapped
6.1.1. Acetone is extremely flammable and
precautions must be taken not to ignite it.
Avoid using large containers or quantities of
acetone. Transfer the solvent in a ventilated
laboratory hood. Do not use acetone near
any open flame. For generation of acetone
vapor, use a spark free heat source.
6.1.2. Any asbestos spills should be cleaned
up immediately to prevent dispersal of fibers. Prudence should be exercised to avoid
contamination of laboratory facilities or exposure of personnel to asbestos. Asbestos
spills should be cleaned up with wet methods
and/or a High Efficiency Particulate-Air
(HEPA) filtered vacuum.
Caution: Do not use a vacuum without a
HEPA filter—It will disperse fine asbestos fibers in the air.
6.2. Equipment
6.2.1. Phase contrast microscope with binocular or trinocular head.
6.2.2. Widefield or Huygenian 10X eyepieces
(NOTE: The eyepiece containing the graticule must be a focusing eyepiece. Use a 40X
phase objective with a numerical aperture of
0.65 to 0.75).
6.2.3. Kohler illumination (if possible) with
green or blue filter.
6.2.4. Walton-Beckett Graticule, type G–22
with 100 ±2 μm projected diameter.
6.2.5. Mechanical stage. A rotating mechanical stage is convenient for use with polarized light.
6.2.6. Phase telescope.
6.2.7. Stage micrometer with 0.01-mm subdivisions.
6.2.8. Phase-shift test slide, mark II (Available from PTR optics Ltd., and also
McCrone).
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31
Occupational Safety and Health Admin., Labor
6.2.9. Precleaned glass slides, 25 mm×75
mm. One end can be frosted for convenience
in writing sample numbers, etc., or paste-on
labels can be used.
6.2.10. Cover glass #11⁄2.
6.2.11. Scalpel (#10, curved blade).
6.2.12. Fine tipped forceps.
6.2.13. Aluminum block for clearing filter
(see appendix D and figure 4).
6.2.14. Automatic adjustable pipette, 100- to
500-μL.
6.2.15. Micropipette, 5 μL.
6.3. Reagents
6.3.1. Acetone (HPLC grade).
6.3.2. Triacetin (glycerol triacetate).
6.3.3. Lacquer or nail polish.
6.4. Standard Preparation
A way to prepare standard asbestos samples of known concentration has not been developed. It is possible to prepare replicate
samples of nearly equal concentration. This
has been performed through the PAT program. These asbestos samples are distributed
by the AIHA to participating laboratories.
Since only about one-fourth of a 25-mm
sample membrane is required for an asbestos
count, any PAT sample can serve as a
‘‘standard’’ for replicate counting.
6.5. Sample Mounting
ally keep the filter on the slide until it is
cleared.
6.5.5. Place the tip of the micropipette containing about 200 μL acetone into the aluminum block. Insert the glass slide into the
receiving slot in the aluminum block. Inject
the acetone into the block with slow, steady
pressure on the plunger while holding the pipette firmly in place. Wait 3 to 5 seconds for
the filter to clear, then remove the pipette
and slide from the aluminum block.
6.5.6. Immediately (less than 30 seconds)
place 2.5 to 3.5 μL of triacetin on the filter
(NOTE: Waiting longer than 30 seconds will
result in increased index of refraction and
decreased contrast between the fibers and
the preparation. This may also lead to separation of the cover slip from the slide).
6.5.7. Lower a cover slip gently onto the filter at a slight angle to reduce the possibility
of forming air bubbles. If more than 30 seconds have elapsed between acetone exposure
and triacetin application, glue the edges of
the cover slip to the slide with lacquer or
nail polish.
6.5.8. If clearing is slow, warm the slide for
15 min on a hot plate having a surface temperature of about 50 °C to hasten clearing.
The top of the hot block can be used if the
slide is not heated too long.
6.5.9. Counting may proceed immediately
after clearing and mounting are completed.
6.6. Sample Analysis
NOTE:
lpowell on DSK54DXVN1OFR with $$_JOB
See Safety Precautions in Section
6.1. before proceeding. The objective is to
produce samples with a smooth (non-grainy)
background in a medium with a refractive
index of approximately 1.46. The technique
below collapses the filter for easier focusing
and produces permanent mounts which are
useful for quality control and interlaboratory comparison.
An aluminum block or similar device is required for sample preparation.
6.5.1. Heat the aluminum block to about 70
°C. The hot block should not be used on any
surface that can be damaged by either the
heat or from exposure to acetone.
6.5.2. Ensure that the glass slides and cover
glasses are free of dust and fibers.
6.5.3. Remove the top plug to prevent a
vacuum when the cassette is opened. Clean
the outside of the cassette if necessary. Cut
the seal and/or tape on the cassette with a
razor blade. Very carefully separate the base
from the extension cowl, leaving the filter
and backup pad in the base.
6.5.4. With a rocking motion cut a triangular wedge from the filter using the scalpel. This wedge should be one-sixth to onefourth of the filter. Grasp the filter wedge
with the forceps on the perimeter of the filter which was clamped between the cassette
pieces. DO NOT TOUCH the filter with your
finger. Place the filter on the glass slide
sample side up. Static electricity will usu-
§ 1915.1001
Completely align the microscope according
to the manufacturer’s instructions. Then,
align the microscope using the following
general alignment routine at the beginning
of every counting session and more often if
necessary.
6.6.1. Alignment
(1) Clean all optical surfaces. Even a small
amount of dirt can significantly degrade the
image.
(2) Rough focus the objective on a sample.
(3) Close down the field iris so that it is
visible in the field of view. Focus the image
of the iris with the condenser focus. Center
the image of the iris in the field of view.
(4) Install the phase telescope and focus on
the phase rings. Critically center the rings.
Misalignment of the rings results in astigmatism which will degrade the image.
(5) Place the phase-shift test slide on the
microscope stage and focus on the lines. The
analyst must see line set 3 and should see at
least parts of 4 and 5 but, not see line set 6
or 6. A microscope/microscopist combination
which does not pass this test may not be
used.
6.6.2. Counting Fibers
(1) Place the prepared sample slide on the
mechanical stage of the microscope. Position
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
the center of the wedge under the objective
lens and focus upon the sample.
(2) Start counting from one end of the
wedge and progress along a radial line to the
other end (count in either direction from perimeter to wedge tip). Select fields randomly, without looking into the eyepieces,
by slightly advancing the slide in one direction with the mechanical stage control.
(3) Continually scan over a range of focal
planes (generally the upper 10 to 15 μm of the
filter surface) with the fine focus control
during each field count. Spend at least 5 to
15 seconds per field.
(4) Most samples will contain asbestos fibers with fiber diameters less than 1 μm.
Look carefully for faint fiber images. The
small diameter fibers will be very hard to
see. However, they are an important contribution to the total count.
(5) Count only fibers equal to or longer
than 5 μm. Measure the length of curved fibers along the curve.
(6) Count fibers which have a length to
width ratio of 3:1 or greater.
(7) Count all the fibers in at least 20 fields.
Continue counting until either 100 fibers are
counted or 100 fields have been viewed;
whichever occurs first. Count all the fibers
in the final field.
(8) Fibers lying entirely within the boundary of the Walton-Beckett graticule field
shall receive a count of 1. Fibers crossing the
boundary once, having one end within the
circle shall receive a count of 1⁄2. Do not
count any fiber that crosses the graticule
boundary more than once. Reject and do not
count any other fibers even though they may
be visible outside the graticule area. If a
fiber touches the circle, it is considered to
cross the line.
(9) Count bundles of fibers as one fiber unless individual fibers can be clearly identified and each individual fiber is clearly not
connected to another counted fiber. See figure 1 for counting conventions.
(10) Record the number of fibers in each
field in a consistent way such that filter
non-uniformity can be assessed.
(11) Regularly check phase ring alignment.
(12) When an agglomerate (mass of material) covers more than 25% of the field of
view, reject the field and select another. Do
not include it in the number of fields counted.
(13) Perform a ‘‘blind recount’’ of 1 in every
10 filter wedges (slides). Re-label the slides
using a person other than the original
counter.
based on morphology, polarized light analysis of fibers, or modification of PCM data
by Scanning Electron or Transmission Electron Microscopy.
A great deal of experience is required to
routinely and correctly perform differential
counting. It is discouraged unless it is legally necessary. Then, only if a fiber is obviously not asbestos should it be excluded from
the count. Further discussion of this technique can be found in reference 8.10.
If there is a question whether a fiber is asbestos or not, follow the rule:
‘‘WHEN IN DOUBT, COUNT.’’
6.8. Analytical Recommendations—Quality
Control System
6.8.1. All individuals performing asbestos
analysis must have taken the NIOSH course
for sampling and evaluating airborne asbestos or an equivalent course.
6.8.2. Each laboratory engaged in asbestos
counting shall set up a slide trading arrangement with at least two other laboratories in
order to compare performance and eliminate
inbreeding of error. The slide exchange occurs at least semiannually. The round robin
results shall be posted where all analysts can
view individual analyst’s results.
6.8.3. Each laboratory engaged in asbestos
counting shall participate in the Proficiency
Analytical Testing Program, the Asbestos
Analyst Registry or equivalent.
6.8.4. Each analyst shall select and count
prepared slides from a ‘‘slide bank’’. These
are quality assurance counts. The slide bank
shall be prepared using uniformly distributed
samples taken from the workload. Fiber densities should cover the entire range routinely
analyzed by the laboratory. These slides are
counted blind by all counters to establish an
original standard deviation. This historical
distribution is compared with the quality assurance counts. A counter must have 95% of
all quality control samples counted within
three standard deviations of the historical
mean. This count is then integrated into a
new historical mean and standard deviation
for the slide.
The analyses done by the counters to establish the slide bank may be used for an interim quality control program if the data are
treated in a proper statistical fashion.
7. Calculations
7.1. Calculate the estimated airborne asbestos fiber concentration on the filter sample
using the following formula:
AC =
⎡⎛ FB ⎞ ⎛ BFB ⎞ ⎤
⎟ ⎥ × ECA
⎟ −⎜
⎢⎜
⎣⎝ FL ⎠ ⎝ BFL ⎠ ⎦
1000 × FR × T × MFA
Where:
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ER10AU94.027
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6.7. Fiber Identification
As previously mentioned in Section 1.3.,
PCM does not provide positive confirmation
of asbestos fibers. Alternate differential
counting techniques should be used if discrimination is desirable. Differential counting may include primary discrimination
Occupational Safety and Health Admin., Labor
7.2. Short-cut Calculation
Since a given analyst always has the same
interpupillary distance, the number of fields
per filter for a particular analyst will remain
constant for a given size filter. The field size
for that analyst is constant (i.e. the analyst
is using an assigned microscope and is not
changing the reticle).
For example, if the exposed area of the filter is always 385 mm2 and the size of the field
is always 0.00785 mm2, the number of fields
per filter will always be 49,000. In addition it
is necessary to convert liters of air to cc.
These three constants can then be combined
such that ECA/(1,000×MFA) = 49. The previous equation simplifies to:
AC =
⎛ FB ⎞ ⎛ BFB ⎞
⎟ × 49
⎟ −⎜
⎜
⎝ FL ⎠ ⎝ BFL ⎠
FR × T
lpowell on DSK54DXVN1OFR with $$_JOB
7.3. Recount Calculations
As mentioned in step 13 of Section 6.6.2., a
‘‘blind recount’’ of 10% of the slides is performed. In all cases, differences will be observed between the first and second counts of
the same filter wedge. Most of these differences will be due to chance alone, that is,
due to the random variability (precision) of
the count method. Statistical recount criteria enables one to decide whether observed
differences can be explained due to chance
alone or are probably due to systematic differences between analysts, microscopes, or
other biasing factors.
The following recount criterion is for a
pair of counts that estimate AC in fibers/cc.
The criterion is given at the type-I error
AC 2 − AC1 > 2.78
×
(
Where:
AC1 = lower estimated airborne fiber concentration
AC2 = higher estimated airborne fiber concentration
ACavg = average of the two concentration estimates
CVFB = CV for the average of the two concentration estimates
If a pair of counts are rejected by this criterion then, recount the rest of the filters in
the submitted set. Apply the test and reject
any other pairs failing the test. Rejection
shall include a memo to the industrial hygienist stating that the sample failed a statistical test for homogeneity and the true air
concentration may be significantly different
than the reported value.
7.4. Reporting Results
Report results to the industrial hygienist
as fibers/cc. Use two significant figures. If
multiple analyses are performed on a sample, an average of the results is to be reported unless any of the results can be rejected for cause.
8. References
8.1. Dreesen, W.C., et al, U.S. Public Health
Service: A Study of Asbestosis in the Asbestos
Textile Industry, (Public Health Bulletin No.
241), US Treasury Dept., Washington, DC,
1938.
8.2. Asbestos Research Council: The Measurement of Airborne Asbestos Dust by the Membrane Filter Method (Technical Note), Asbestos Research Council, Rockdale, Lancashire,
Great Britain, 1969.
8.3. Bayer, S.G., Zumwalde, R.D., Brown,
T.A., Equipment and Procedure for Mounting
Millipore Filters and Counting Asbestos Fibers
by Phase Contrast Microscopy, Bureau of Occupational Health, U.S. Dept. of Health, Education and Welfare, Cincinnati,OH,1969.
8.4. NIOSH Manual of Analytical Methods,
2nd ed., Vol. 1 (DHEW/NIOSH Pub. No. 77–
157–A). National Institute for Occupational
Safety
and
Health,
Cincinnati,
OH,
1977.pp.239–1–239–21.
8.5. Asbestos, Code of Federal Regulations
29 CFR 1910.1001. 1971.
8.6. Occupational Exposure to Asbestos,
Tremolite, Anthophyllite, and Actinolite. Final
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ER29JN95.001
NOTE: The collection area of a filter is seldom equal to 385 mm2. It is appropriate for
laboratories to routinely monitor the exact
diameter using an inside micrometer. The
collection area is calculated according to the
formula:
Area = π(d/2) 2
level. That is, there is 5% maximum risk
that we will reject a pair of counts for the
reason that one might be biased, when the
large observed difference is really due to
chance.
Reject a pair of counts if:
ER10AU94.028
AC = Airborne fiber concentration
FB = Total number of fibers greater than 5
μm counted
FL = Total number of fields counted on the
filter
BFB = Total number of fibers greater than 5
μm counted in the blank
BFL = Total number of fields counted on the
blank
ECA = Effective collecting area of filter (385
mm2 nominal for a 25-mm filter.)
FR = Pump flow rate (L/min)
MFA = Microscope count field area (mm2 ).
This is 0.00785 mm2 for a Walton-Beckett
Graticule.
T = Sample collection time (min)
1,000 = Conversion of L to cc
§ 1915.1001
§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
lpowell on DSK54DXVN1OFR with $$_JOB
⎛P ⎞ ⎛T ⎞
Q act = Q cal × ⎜ cal ⎟ × ⎜ act ⎟
⎝ Pact ⎠ ⎝ Tcal ⎠
dc =
AL × D
PL
Example: If PL=108 μm, AL=2.93 mm and
D=100 μm, then,
dc =
2.93 × 100
108
= 2.71mm
(7) Each eyepiece-objective-reticle combination on the microscope must be calibrated. Should any of the three be changed
(by zoom adjustment, disassembly, replacement, etc.), the combination must be recalibrated. Calibration may change if interpupillary distance is changed.
Measure the field diameter, D (acceptable
range: 100 ±2 μm) with a stage micrometer
upon receipt of the graticule from the manufacturer. Determine the field area (mm2).
Field Area= π(D/2)2
If D=100 μm=0.1 mm, then
Field Area=π(0.1 mm/2)2=0.00785 mm2
The Graticule is available from: Graticules
Ltd., Morley Road, Tonbridge TN9 IRN,
Kent, England (Telephone 011–44–732–359061).
Also available from PTR Optics Ltd., 145
Newton Street, Waltham, MA 02154 [telephone (617) 891–6000] or McCrone Accessories
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ER10AU94.032
Sampling Pump Flow Rate Corrections
This correction is used if a difference
greater than 5% in ambient temperature and/
or pressure is noted between calibration and
sampling sites and the pump does not compensate for the differences.
Walton-Beckett Graticule
When ordering the Graticule for asbestos
counting, specify the exact disc diameter
needed to fit the ocular of the microscope
and the diameter (mm) of the circular counting area. Instructions for measuring the dimensions necessary are listed:
(1) Insert any available graticule into the
focusing eyepiece and focus so that the graticule lines are sharp and clear.
(2) Align the microscope.
(3) Place a stage micrometer on the microscope object stage and focus the microscope
on the graduated lines.
(4) Measure the magnified grid length, PL
(μm), using the stage micrometer.
(5) Remove the graticule from the microscope and measure its actual grid length, AL
(mm). This can be accomplished by using a
mechanical stage fitted with verniers, or a
jeweler’s loupe with a direct reading scale.
(6) Let D=100 μm. Calculate the circle diameter, dc (mm), for the Walton-Beckett
graticule and specify the diameter when
making a purchase:
ER10AU94.031
Quality Control
The OSHA asbestos regulations require
each laboratory to establish a quality control program. The following is presented as
an example of how the OSHA-SLTC constructed its internal CV curve as part of
meeting this requirement. Data is from 395
samples collected during OSHA compliance
inspections and analyzed from October 1980
through April 1986.
Each sample was counted by 2 to 5 different counters independently of one another. The standard deviation and the CV
statistic was calculated for each sample.
This data was then plotted on a graph of CV
vs. fibers/mm2. A least squares regression
was performed using the following equation:
CV = antilog10[A(log10(x))2+B(log10(x))+C]
Where:
x = the number of fibers/mm2
Application of least squares gave:
A = 0.182205
B = ¥0.973343
C = 0.327499
Using these values, the equation becomes:
CV = antilog10[0.182205(log10 (x))2¥0.973343(log
10(x))+0.327499]
Where:
Qact = actual flow rate
Qcal = calibrated flow rate (if a rotameter was
used, the rotameter value)
Pcal = uncorrected air pressure at calibration
Pact = uncorrected air pressure at sampling
site
Tact = temperature at sampling site (K)
Tcal = temperature at calibration (K)
ER10AU94.030
Rule, FEDERAL REGISTER 51: 119 (20 June
1986). pp.22612–22790.
8.7. Asbestos, Tremolite, Anthophyllite, and
Actinolite, Code of Federal Regulations
1910.1001. 1988. pp 711–752.
8.8. Criteria for a Recommended Standard—
Occupational Exposure to Asbestos (DHEW/
NIOSH Pub. No. HSM 72–10267), National Institute for Occupational Safety and Health
NIOSH, Cincinnati, OH, 1972. pp. III–1–III–24.
8.9. Leidel, N.A., Bayer, S.G., Zumwalde,
R.D., Busch, K.A., USPHS/NIOSH Membrane
Filter Method for Evaluating Airborne Asbestos
Fibers (DHEW/NIOSH Pub. No. 79–127). National Institute for Occupational Safety and
Health, Cincinnati, OH, 1979.
8.10. Dixon, W.C., Applications of Optical Microscopy in Analysis of Asbestos and Quartz,
Analytical Techniques in Occupational
Health Chemistry, edited by D.D. Dollberg
and A.W. Verstuyft. Wash. D.C.: American
Chemical Society, (ACS Symposium Series
120) 1980. pp. 13–41.
Occupational Safety and Health Admin., Labor
§ 1915.1001
and Components, 2506 S. Michigan Ave., Chicago, IL 60616 [phone (312) 842–7100]. The graticule is custom made for each microscope.
COUNTS FOR THE FIBERS IN THE FIGURE
Structure No.
Count
1
1⁄2
0
2
0
0
1⁄2
Explanation
Single fibers all contained within the circle.
Fiber crosses circle once.
Fiber too short.
Two crossing fibers.
Fiber outside graticule.
Fiber crosses graticule twice.
Although split, fiber only crosses once.
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1 to 6 ....................................
7 ............................................
8 ............................................
9 ............................................
10 ..........................................
11 ..........................................
12 ..........................................
§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
APPENDIX C TO § 1915.1001—QUALITATIVE AND
QUANTITATIVE FIT TESTING PROCEDURES.
MANDATORY
Employers must perform fit testing in accordance with the fit-testing requirements of
29 CFR 1910.134(f) and the qualitative and
quantitative fit-testing protocols and procedures specified in Appendix A of 29 CFR
1910.134.
APPENDIX D TO § 1915.1001—MEDICAL
QUESTIONNAIRES. MANDATORY
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This mandatory appendix contains the
medical questionnaires that must be administered to all employees who are exposed to
asbestos, tremolite, anthophyllite, actinolite, or a combination of these minerals
above the permissible exposure limit (0.1 f/
cc), and who will therefore be included in
their employer’s medical surveillance program. Part 1 of the appendix contains the
Initial Medical Questionnaire, which must be
obtained for all new hires who will be covered by the medical surveillance requirements. Part 2 includes the abbreviated Periodical Medical Questionnaire, which must be
administered to all employees who are provided periodic medical examinations under
the medical surveillance provisions of the
standard.
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§ 1915.1001
Occupational Safety and Health Admin., Labor
APPENDIX E TO § 1915.1001—INTERPRETATION
AND CLASSIFICATION OF CHEST ROENTGENOGRAMS. MANDATORY
(a) Chest roentgenograms shall be interpreted and classified in accordance with a
professionally accepted classification system
and recorded on an interpretation form following the format of the CDC/NIOSH (M) 2.8
form. As a minimum, the content within the
bold lines of this form (items 1 through 4)
shall be included. This form is not to be submitted to NIOSH.
(b) Roentgenograms shall be interpreted
and classified only by a B-reader, a board eligible/certified radiologist, or an experienced
physician
with
known
expertise
in
pneumoconioses.
(c) All interpreters, whenever interpreting
chest roentgenograms made under this section, shall have immediately available for
reference a complete set of the ILO-U/C
International Classification of Radiographs
for Pneumoconioses, 1980.
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APPENDIX F TO § 1915.1001—WORK PRACTICES
AND ENGINEERING CONTROLS FOR CLASS I
ASBESTOS OPERATIONS NON-MANDATORY
This is a non-mandatory appendix to the
asbestos standards for construction and for
shipyards. It describes criteria and procedures for erecting and using negative pressure enclosures for Class I Asbestos Work,
when NPEs are used as an allowable control
method to comply with paragraph (g)(5) (i) of
this section. Many small and variable details
are involved in the erection of a negative
pressure enclosure. OSHA and most participants in the rulemaking agreed that only the
major, more performance oriented criteria
should be made mandatory. These criteria
are set out in paragraph (g) of this section.
In addition, this appendix includes these
mandatory specifications and procedures in
its guidelines in order to make this appendix
coherent and helpful. The mandatory nature
of the criteria which appear in the regulatory text is not changed because they are
included in this ‘‘non-mandatory’’ appendix.
Similarly, the additional criteria and procedures included as guidelines in the appendix,
do not become mandatory because mandatory criteria are also included in these comprehensive guidelines.
In addition, none of the criteria, both mandatory and recommended, are meant to
specify or imply the need for use of patented
or licensed methods or equipment. Recommended specifications included in this attachment should not discourage the use of
creative alternatives which can be shown to
reliably achieve the objectives of negativepressure enclosures.
Requirements included in this appendix,
cover general provisions to be followed in all
asbestos jobs, provisions which must be followed for all Class I asbestos jobs, and provi-
§ 1915.1001
sions governing the construction and testing
of negative pressure enclosures. The first
category includes the requirement for use of
wet methods, HEPA vacuums, and immediate bagging of waste; Class I work must
conform to the following provisions:
• oversight by competent person
• use of critical barriers over all openings
to work area
• isolation of HVAC systems
• use of impermeable dropcloths and coverage of all objects within regulated areas
In addition, more specific requirements for
NPEs include:
• maintenance of ¥0.02 inches water gauge
within enclosure
• manometric measurements
• air movement away from employees performing removal work
• smoke testing or equivalent for detection
of leaks and air direction
• deactivation of electrical circuits, if not
provided with ground-fault circuit interrupters.
Planning the Project
The standard requires that an exposure assessment be conducted before the asbestos
job is begun § 1915.1001(f)(1). Information
needed for that assessment, includes data relating to prior similar jobs, as applied to the
specific variables of the current job. The information needed to conduct the assessment
will be useful in planning the project, and in
complying with any reporting requirements
under this standard, when significant
changes are being made to a control system
listed in the standard, [see paragraph (k) of
this section], as well as those of USEPA (40
CFR part 61, subpart M). Thus, although the
standard does not explicitly require the preparation of a written asbestos removal plan,
the usual constituents of such a plan, i.e., a
description of the enclosure, the equipment,
and the procedures to be used throughout the
project, must be determined before the enclosure can be erected. The following information should be included in the planning of
the system:
A physical description of the work area;
A description of the approximate amount
of material to be removed;
A schedule for turning off and sealing existing ventilation systems;
Personnel hygiene procedures;
A description of personal protective equipment and clothing to worn by employees;
A description of the local exhaust ventilation systems to be used and how they are to
be tested;
A description of work practices to be observed by employees;
An air monitoring plan;
A description of the method to be used to
transport waste material; and
The location of the dump site.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
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Materials and Equipment Necessary for Asbestos
Removal
Although individual asbestos removal
projects vary in terms of the equipment required to accomplish the removal of the materials, some equipment and materials are
common to most asbestos removal operations.
Plastic sheeting used to protect horizontal
surfaces, seal HVAC openings or to seal
vertical openings and ceilings should have a
minimum thickness of 6 mils. Tape or other
adhesive used to attach plastic sheeting
should be of sufficient adhesive strength to
support the weight of the material plus all
stresses encountered during the entire duration of the project without becoming detached from the surface.
Other equipment and materials which
should be available at the beginning of each
project are:
—HEPA Filtered Vacuum is essential for
cleaning the work area after the asbestos has
been removed. It should have a long hose capable of reaching out-of-the-way places, such
as areas above ceiling tiles, behind pipes,
etc.
—Portable air ventilation systems installed to provide the negative air pressure
and air removal from the enclosure must be
equipped with a HEPA filter. The number
and capacity of units required to ventilate
an enclosure depend on the size of the area
to be ventilated. The filters for these systems should be designed in such a manner
that they can be replaced when the air flow
volume is reduced by the build-up of dust in
the filtration material. Pressure monitoring
devices with alarms and strip chart recorders
attached to each system to indicate the pressure differential and the loss due to dust
buildup on the filter are recommended.
—Water sprayers should be used to keep the
asbestos material as saturated as possible
during removal; the sprayers will provide a
fine mist that minimizes the impact of the
spray on the material.
—Water used to saturate the asbestos containing material can be amended by adding
at least 15 milliliters (1⁄4 ounce) of wetting
agent in 1 liter (1 pint) of water. An example of a wetting agent is a 50/50 mixture of
polyoxyethylene
ether
and
polyoxyethylene polyglycol ester.
—Backup power supplies are recommended,
especially for ventilation systems.
—Shower and bath water should be with
mixed hot and cold water faucets. Water
that has been used to clean personnel or
equipment should either be filtered or be
collected and discarded as asbestos waste.
Soap and shampoo should be provided to
aid in removing dust from the workers’
skin and hair.
—See paragraphs (h) and (i) of this section
for appropriate respiratory protection and
protective clothing.
—See paragraph (k) of this section for required signs and labels.
Preparing the Work Area
Disabling HVAC Systems: The power to
the heating, ventilation, and air conditioning systems that service the restricted
area must be deactivated and locked off. All
ducts, grills, access ports, windows and vents
must be sealed off with two layers of plastic
to prevent entrainment of contaminated air.
Operating HVAC Systems in the Restricted
Area: If components of a HVAC system located in the restricted area are connected to
a system that will service another zone during the project, the portion of the duct in the
restricted area must be sealed and pressurized. Necessary precautions include caulking
the duct joints, covering all cracks and openings with two layers of sheeting, and pressurizing the duct throughout the duration of
the project by restricting the return air flow.
The power to the fan supplying the positive
pressure should be locked ‘‘on’’ to prevent
pressure loss.
Sealing Elevators: If an elevator shaft is
located in the restricted area, it should be either shut down or isolated by sealing with
two layers of plastic sheeting. The sheeting
should provide enough slack to accommodate the pressure changes in the shaft without breaking the air-tight seal.
Removing Mobile Objects: All movable objects should be cleaned and removed from
the work area before an enclosure is constructed unless moving the objects creates a
hazard. Mobile objects will be assumed to be
contaminated and should be either cleaned
with amended water and a HEPA vacuum
and then removed from the area or wrapped
and then disposed of as hazardous waste.
Cleaning and Sealing Surfaces: After
cleaning with water and a HEPA vacuum,
surfaces of stationary objects should be covered with two layers of plastic sheeting. The
sheeting should be secured with duct tape or
an equivalent method to provide a tight seal
around the object.
Bagging Waste: In addition to the requirement for immediate bagging of waste for disposal, it is further recommended that the
waste material be double-bagged and sealed
in plastic bags designed for asbestos disposal.
The bags should be stored in a waste storage
area that can be controlled by the workers
conducting the removal. Filters removed
from air handling units and rubbish removed
from the area are to be bagged and handled
as hazardous waste.
Constructing the Enclosure
The enclosure should be constructed to
provide an air-tight seal around ducts and
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Occupational Safety and Health Admin., Labor
openings into existing ventilation systems
and around penetrations for electrical conduits, telephone wires, water lines, drain
pipes, etc. Enclosures should be both airtight
and watertight except for those openings designed to provide entry and/or air flow control.
Size: An enclosure should be the minimum
volume to encompass all of the working surfaces yet allow unencumbered movement by
the worker(s), provide unrestricted air flow
past the worker(s), and ensure walking surfaces can be kept free of tripping hazards.
Shape: The enclosure may be any shape
that optimizes the flow of ventilation air
past the worker(s).
Structural Integrity: The walls, ceilings
and floors must be supported in such a manner that portions of the enclosure will not
fall down during normal use.
Openings: It is not necessary that the
structure be airtight; openings may be designed to direct air flow. Such openings
should be located at a distance from active
removal operations. They should be designed
to draw air into the enclosure under all anticipated circumstances. In the event that
negative pressure is lost, they should be
fitted with either HEPA filters to trap dust
or automatic trap doors that prevent dust
from escaping the enclosure. Openings for
exits should be controlled by an airlock or a
vestibule.
Barrier Supports: Frames should be constructed to support all unsupported spans of
sheeting.
Sheeting: Walls, barriers, ceilings, and
floors should be lined with two layers of
plastic sheeting having a thickness of at
least 6 mil.
Seams: Seams in the sheeting material
should be minimized to reduce the possibilities of accidental rips and tears in the adhesive or connections. All seams in the sheeting should overlap, be staggered and not be
located at corners or wall-to- floor joints.
Areas Within an Enclosure: Each enclosure
consists of a work area, a decontamination
area, and waste storage area. The work area
where the asbestos removal operations occur
should be separated from both the waste
storage area and the contamination control
area by physical curtains, doors, and/or airflow patterns that force any airborne contamination back into the work area.
See paragraph (j) of § 1915.1001 for requirements for hygiene facilities.
During egress from the work area, each
worker should step into the equipment room,
clean tools and equipment, and remove gross
contamination from clothing by wet cleaning and HEPA vacuuming. Before entering
the shower area, foot coverings, head coverings, hand coverings, and coveralls are removed and placed in impervious bags for disposal or cleaning. Airline connections from
airline respirators with HEPA disconnects
§ 1915.1001
and power cables from powered air-purifying
respirators (PAPRs) will be disconnected
just prior to entering the shower room.
Establishing Negative Pressure Within the
Enclosure
Negative Pressure: Air is to be drawn into
the enclosure under all anticipated conditions and exhausted through a HEPA filter
for 24 hours a day during the entire duration
of the project.
Air Flow Tests: Air flow patterns will be
checked before removal operations begin, at
least once per operating shift and any time
there is a question regarding the integrity of
the enclosure. The primary test for air flow
is to trace air currents with smoke tubes or
other visual methods. Flow checks are made
at each opening and at each doorway to demonstrate that air is being drawn into the enclosure and at each worker’s position to
show that air is being drawn away from the
breathing zone.
Monitoring Pressure Within the Enclosure:
After the initial air flow patterns have been
checked, the static pressure must be monitored within the enclosure. Monitoring may
be made using manometers, pressure gauges,
or combinations of these devices. It is recommended that they be attached to alarms
and strip chart recorders at points identified
by the design engineer.
Corrective Actions: If the manometers or
pressure gauges demonstrate a reduction in
pressure differential below the required
level, work should cease and the reason for
the change investigated and appropriate
changes made. The air flow patterns should
be retested before work begins again.
Pressure Differential: The design parameters for static pressure differentials between the inside and outside of enclosures
typically range from 0.02 to 0.10 inches of
water gauge, depending on conditions. All
zones inside the enclosure must have less
pressure than the ambient pressure outside
of the enclosure (–0.02 inches water gauge
differential). Design specifications for the
differential vary according to the size, configuration, and shape of the enclosure as well
as ambient and mechanical air pressure conditions around the enclosure.
Air Flow Patterns: The flow of air past
each worker shall be enhanced by positioning the intakes and exhaust ports to remove contaminated air from the worker’s
breathing zone, by positioning HEPA vacuum cleaners to draw air from the worker’s
breathing zone, by forcing relatively
uncontaminated air past the worker toward
an exhaust port, or by using a combination
of methods to reduce the worker’s exposure.
Air Handling Unit Exhaust: The exhaust
plume from air handling units should be located away from adjacent personnel and intakes for HVAC systems.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
Air Flow Volume: The air flow volume
(cubic meters per minute) exhausted (removed) from the workplace must exceed the
amount of makeup air supplied to the enclosure. The rate of air exhausted from the enclosure should be designed to maintain a
negative pressure in the enclosure and air
movement past each worker. The volume of
air flow removed from the enclosure should
replace the volume of the container at every
5 to 15 minutes. Air flow volume will need to
be relatively high for large enclosures, enclosures with awkward shapes, enclosures with
multiple openings, and operations employing
several workers in the enclosure.
Air Flow Velocity: At each opening, the air
flow velocity must visibly ‘‘drag’’ air into
the enclosure. The velocity of air flow within
the enclosure must be adequate to remove
airborne contamination from each worker’s
breathing zone without disturbing the asbestos-containing material on surfaces.
Airlocks: Airlocks are mechanisms on
doors and curtains that control the air flow
patterns in the doorways. If air flow occurs,
the patterns through doorways must be such
that the air flows toward the inside of the
enclosure. Sometimes vestibules, double
doors, or double curtains are used to prevent
air movement through the doorways. To use
a vestibule, a worker enters a chamber by
opening the door or curtain and then closing
the entry before opening the exit door or
curtain.
Airlocks should be located between the
equipment room and shower room, between
the shower room and the clean room, and between the waste storage area and the outside
of the enclosure. The air flow between adjacent rooms must be checked using smoke
tubes or other visual tests to ensure the flow
patterns draw air toward the work area without producing eddies.
Monitoring for Airborne Concentrations
In addition to the breathing zone samples
taken as outlined in paragraph (f) of
§ 1915.1001 , samples of air should be taken to
demonstrate the integrity of the enclosure,
the cleanliness of the clean room and shower
area, and the effectiveness of the HEPA filter. If the clean room is shown to be contaminated, the room must be relocated to an
uncontaminated area.
Samples taken near the exhaust of portable ventilation systems must be done with
care.
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General Work Practices
Preventing dust dispersion is the primary
means of controlling the spread of asbestos
within the enclosure. Whenever practical,
the point of removal should be isolated, enclosed, covered, or shielded from the workers
in the area. Waste asbestos containing materials must be bagged during or immediately
after removal; the material must remain
saturated until the waste container is sealed.
Waste material with sharp points or corners must be placed in hard air-tight containers rather than bags.
Whenever possible, large components
should be sealed in plastic sheeting and removed intact.
Bags or containers of waste will be moved
to the waste holding area, washed, and
wrapped in a bag with the appropriate labels.
Cleaning the Work Area
Surfaces within the work area should be
kept free of visible dust and debris to the extent feasible. Whenever visible dust appears
on surfaces, the surfaces within the enclosure must be cleaned by wiping with a wet
sponge, brush, or cloth and then vacuumed
with a HEPA vacuum.
All surfaces within the enclosure should be
cleaned before the exhaust ventilation system is deactivated and the enclosure is disassembled. An approved encapsulant may be
sprayed onto areas after the visible dust has
been removed.
APPENDIX G TO § 1915.1001 [RESERVED]
APPENDIX H TO § 1915.1001—SUBSTANCE TECHNICAL INFORMATION FOR ASBESTOS. NONMANDATORY
I. Substance Identification
A. Substance: ‘‘Asbestos’’ is the name of a
class of magnesium-silicate minerals that
occur in fibrous form. Minerals that are included in this group are chrysotile, crocidolite,
amosite,
anthophyllite
asbestos,
tremolite asbestos, and actinolite asbestos.
B. Asbestos is and was used in the manufacture of heat-resistant clothing, automotive brake and clutch linings, and a variety of building materials including floor
tiles, roofing felts, ceiling tiles, asbestos-cement pipe and sheet, and fire-resistant
drywall. Asbestos is also present in pipe and
boiler insulation materials and in sprayed-on
materials located on beams, in crawlspaces,
and between walls.
C. The potential for an asbestos-containing
product to release breathable fibers depends
largely on its degree of friability. Friable
means that the material can be crumbled
with hand pressure and is therefore likely to
emit fibers. The fibrous fluffy sprayed-on
materials used for fireproofing, insulation,
or sound proofing are considered to be friable, and they readily release airborne fibers
if disturbed. Materials such as vinyl-asbestos
floor tile or roofing felt are considered nonfriable if intact and generally do not emit
airborne fibers unless subjected to sanding,
sawing and other aggressive operations. Asbestos—cement pipe or sheet can emit airborne fibers if the materials are cut or
sawed, or if they are broken.
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Occupational Safety and Health Admin., Labor
D. Permissible exposure: Exposure to airborne asbestos fibers may not exceed 0.1 fibers per cubic centimeter of air (0.1 f/cc)
averaged over the 8-hour workday, and 1
fiber per cubic centimeter of air (1.0 f/cc)
averaged over a 30 minute work period.
II. Health Hazard Data
A. Asbestos can cause disabling respiratory
disease and various types of cancers if the fibers are inhaled. Inhaling or ingesting fibers
from contaminated clothing or skin can also
result in these diseases. The symptoms of
these diseases generally do not appear for 20
or more years after initial exposure.
B. Exposure to asbestos has been shown to
cause lung cancer, mesothelioma, and cancer
of the stomach and colon. Mesothelioma is a
rare cancer of the thin membrane lining of
the chest and abdomen. Symptoms of mesothelioma include shortness of breath, pain in
the walls of the chest, and/or abdominal
pain.
§ 1915.1001
B. Empty shipping bags can be flattened
under exhaust hoods and packed into airtight containers for disposal. Empty shipping drums are difficult to clean and should
be sealed.
C. Vacuum bags or disposable paper filters
should not be cleaned, but should be sprayed
with a fine water mist and placed into a labeled waste container.
D. Process waste and housekeeping waste
should be wetted with water or a mixture of
water and surfactant prior to packaging in
disposable containers.
E. Asbestos-containing material that is removed from buildings must be disposed of in
leak-tight 6-mil plastic bags, plastic-lined
cardboard containers, or plastic-lined metal
containers. These wastes, which are removed
while wet, should be sealed in containers before they dry out to minimize the release of
asbestos fibers during handling.
V. Access to Information
III. Respirators and Protective Clothing
A. Respirators: You are required to wear a
respirator when performing tasks that result
in asbestos exposure that exceeds the permissible exposure limit (PEL) of 0.1 f/cc and
when performing certain designated operations. Air-purifying respirators equipped
with a high-efficiency particulate air
(HEPA) filter can be used where airborne asbestos fiber concentrations do not exceed 1.0
f/cc; otherwise, more protective respirators
such as air-supplied, positive-pressure, full
facepiece respirators must be used. Disposable respirators or dust masks are not permitted to be used for asbestos work. For effective protection, respirators must fit your
face and head snugly. Your employer is required to conduct a fit test when you are
first assigned a respirator and every 6
months thereafter. Respirators should not be
loosened or removed in work situations
where their use is required.
B. Protective Clothing: You are required to
wear protective clothing in work areas where
asbestos fiber concentrations exceed the permissible exposure limit (PEL) of 0.1 f/cc.
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IV. Disposal Procedures and Clean-up
A. Wastes that are generated by processes
where asbestos is present include:
1. Empty asbestos shipping containers.
2. Process wastes such as cuttings, trimmings, or reject materials.
3. Housekeeping waste from wet-sweeping
or HEPA-vacuuming.
4. Asbestos fireproofing or insulating material that is removed from buildings.
5. Asbestos-containing building products
removed during building renovation or demolition.
6. Contaminated disposable protective
clothing.
A. Each year, your employer is required to
inform you of the information contained in
this standard and appendices for asbestos. In
addition, your employer must instruct you
in the proper work practices for handling asbestos-containing materials, and the correct
use of protective equipment.
B. Your employer is required to determine
whether you are being exposed to asbestos.
Your employer must treat exposure to thermal system insulation and sprayed-on and
troweled-on surfacing material as asbestos
exposure, unless results of laboratory analysis show that the material does not contain
asbestos. You or your representative has the
right to observe employee measurements and
to record the results obtained. Your employer is required to inform you of your exposure, and, if you are exposed above the permissible exposure limit, he or she is required
to inform you of the actions that are being
taken to reduce your exposure to within the
permissible limit.
C. Your employer is required to keep
records of your exposures and medical examinations. These exposure records must be
kept for at least thirty (30) years. Medical
records must be kept for the period of your
employment plus thirty (30) years.
D. Your employer is required to release
your exposure and medical records to your
physician or designated representative upon
your written request.
APPENDIX I TO § 1915.1001—MEDICAL SURVEILLANCE GUIDELINES FOR ASBESTOS, NONMANDATORY
I. Route of Entry
Inhalation, ingestion.
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31
§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
II. Toxicology
Clinical evidence of the adverse effects associated with exposure to asbestos is present
in the form of several well- conducted epidemiological studies of occupationally exposed
workers, family contacts of workers, and
persons living near asbestos mines. These
studies have shown a definite association between exposure to asbestos and an increased
incidence of lung cancer, pleural and peritoneal mesothelioma, gastrointestinal cancer, and asbestosis. The latter is a disabling
fibrotic lung disease that is caused only by
exposure to asbestos. Exposure to asbestos
has also been associated with an increased
incidence of esophageal, kidney, laryngeal,
pharyngeal, and buccal cavity cancers. As
with other known chronic occupational diseases, disease associated with asbestos generally appears about 20 years following the
first occurrence of exposure: There are no
known acute effects associated with exposure to asbestos.
Epidemiological studies indicate that the
risk of lung cancer among exposed workers
who smoke cigarettes is greatly increased
over the risk of lung cancer among non-exposed smokers or exposed nonsmokers. These
studies suggest that cessation of smoking
will reduce the risk of lung cancer for a person exposed to asbestos but will not reduce it
to the same level of risk as that existing for
an exposed worker who has never smoked.
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III. Signs and Symptoms of Exposure Related
Disease
The signs and symptoms of lung cancer or
gastrointestinal cancer induced by exposure
to asbestos are not unique, except that a
chest X-ray of an exposed patient with lung
cancer may show pleural plaques, pleural
calcification, or pleural fibrosis. Symptoms
characteristic of mesothelioma include
shortness of breath, pain in the walls of the
chest, or abdominal pain. Mesothelioma has
a much longer latency period compared with
lung cancer (40 years versus 15–20 years), and
mesothelioma is therefore more likely to be
found among workers who were first exposed
to asbestos at an early age. Mesothelioma is
always fatal.
Asbestosis is pulmonary fibrosis caused by
the accumulation of asbestos fibers in the
lungs. Symptoms include shortness of
breath, coughing, fatigue, and vague feelings
of sickness. When the fibrosis worsens, shortness of breath occurs even at rest. The diagnosis of asbestosis is based on a history of
exposure to asbestos, the presence of characteristics radiologic changes, end-inspiratory
crackles (rales), and other clinical features
of fibrosing lung disease. Pleural plaques and
thickening are observed on X-rays taken
during the early sates of the disease. Asbestosis is often a progressive disease even in
the absence of continued exposure, although
this appears to be a highly individualized
characteristic. In severe cases, death may be
caused by respiratory or cardiac failure.
IV. Surveillance and Preventive Considerations
As noted above, exposure to asbestos have
been linked to an increased risk of lung cancer, mesothelioma, gastrointestinal cancer,
and asbestosis among occupationally exposed workers. Adequate screening tests to
determine an employee’s potential for developing serious chronic diseases, such as a cancer, from exposure to asbestos do not presently exist. However, some tests, particularly chest X-rays and pulmonary function
tests, may indicate that an employee has
been overexposed to asbestos increasing his
or her risk of developing exposure related
chronic diseases. It is important for the physician to become familiar with the operating
conditions in which occupational exposure to
asbestos is likely to occur. This is particularly important in evaluating medical and
work histories and in conducting physical
examinations. When an active employee has
been identified as having been overexposed
to asbestos measures taken by the employer
to eliminate or mitigate further exposure
should also lower the risk of serious longterm consequences.
The employer is required to institute a
medical surveillance program for all employees who are or will be exposed to asbestos at
or above the permissible exposure limits (0.1
fiber per cubic centimeter of air) for 30 or
more days per year and for all employees
who are assigned to wear a negative-pressure
respirator. All examinations and procedures
must be performed by or under the supervision of licensed physician at a reasonable
time and place, and at no cost to the employee.
Although broad latitude is given to the
physician in prescribing specific tests to be
included in the medical surveillance program, OSHA requires inclusion of the following elements in the routine examination,
(i) Medical and work histories with special
emphasis directed to symptoms of the respiratory system, cardiovascular system, and
digestive tract.
(ii) Completion of the respiratory disease
questionnaire contained in appendix D to
this section.
(iii) A physical examination including a
chest roentgenogram and pulmonary function test that include measurement of the
employee’s forced vital capacity (FYC) and
forced expiratory volume at one second
(FEV1).
(iv) Any laboratory or other test that the
examining physician deems by sound medical practice to be necessary.
The employer is required to make the prescribed tests available at least annually to
those employees covered; more often than
specified if recommended by the examining
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Occupational Safety and Health Admin., Labor
physician; and upon termination of employment.
The employer is required to provide the
physician with the following information: A
copy of this standard and appendices; a description of the employee’s duties as they relate to asbestos exposure; the employee’s
representative level of exposure to asbestos;
a description of any personal protective and
respiratory equipment used; and information
from previous medical examinations of the
affected employee that is not otherwise
available to the physician. Making this information available to the physician will aid
in the evaluation of the employee’s health in
relation to assigned duties and fitness to
wear personal protective equipment, if required.
The employer is required to obtain a written opinion from the examining physician
containing the results of the medical examination; the physician’s opinion as to whether the employee has any detected medical
conditions that would place the employee at
an increased risk of exposure-related disease;
any recommended limitations on the employee or on the use of personal protective
equipment; and a statement that the employee has been informed by the physician of
the results of the medical examination and
of any medical conditions related to asbestos
exposure that require further explanation or
treatment. This written opinion must not reveal specific findings or diagnoses unrelated
to exposure to asbestos, and a copy of the
opinion must be provided to the affected employee.
J TO § 1915.1001—SMOKING CESSATION PROGRAM INFORMATION FOR ASBESTOS—NON-MANDATORY
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APPENDIX
The following organizations provide smoking cessation information.
1. The National Cancer Institute operates a
toll-free Cancer Information Service (CIS)
with trained personnel to help you. Call 1–
800–4–CANCER* to reach the CIS office serving your area, or write: Office of Cancer
Communications, National Cancer Institute,
National Institutes of Health, Building 31,
Room 10A24, Bethesda, Maryland 20892.
2. American Cancer Society, 3340 Peachtree
Road, N.E., Atlanta, Georgia 30026, (404) 320–
3333.
The American Cancer Society (ACS) is a
voluntary organization composed of 58 divisions and 3,100 local units. Through ‘‘The
Great American Smokeout’’ in November,
the annual Cancer Crusade in April, and numerous educational materials, ACS helps
people learn about the health hazards of
smoking and become successful ex-smokers.
3. American Heart Association, 7320 Greenville Avenue, Dallas, Texas 75231, (214) 750–
5300.
The American Heart Association (AHA) is
a voluntary organization with 130,000 mem-
§ 1915.1001
bers (physicians, scientists, and laypersons)
in 55 state and regional groups. AHA produces a variety of publications and audiovisual materials about the effects of smoking on the heart. AHA also has developed a
guidebook for incorporating a weight-control
component into smoking cessation programs.
4. American Lung Association, 1740 Broadway, New York, New York 10019, (212) 245–
8000.
A voluntary organization of 7,500 members
(physicians, nurses, and laypersons), the
American Lung Association (ALA) conducted
numerous public information programs
about the health effects of smoking. ALA
has 59 state and 85 local units. The organization actively supports legislation and information campaigns for non-smokers’ rights
and provides help for smokers who want to
quit, for example, through ‘‘Freedom From
Smoking,’’ a self-help smoking cessation
program.
5. Office on Smoking and Health, U.S. Department of Health and Human Services 5600
Fishers Lane, Park Building, Room 110,
Rockville, Maryland 20857.
The Office on Smoking and Health (OSHA)
is the Department of Health and Human
Services’ lead agency in smoking control.
OSHA has sponsored distribution of publications on smoking-related topics, such as free
flyers on relapse after initial quitting, helping a friend or family member quit smoking,
the health hazards of smoking, and the effects of parental smoking on teenagers.
*In Hawaii, on Oahu call 524–1234 (call collect from neighboring islands),
Spanish-speaking staff members are available during daytime hours to callers from
the following areas: California, Florida,
Georgia, Illinois, New Jersey (area code 201),
New York, and Texas. Consult your local
telephone directory for listings of local chapters.
APPENDIX K TO § 1915.1001—POLARIZED LIGHT
MICROSCOPY OF ASBESTOS—NON-MANDATORY
Method number: ID–191
Matrix: Bulk
Collection Procedure
Collect approximately 1 to 2 grams of each
type of material and place into separate 20
mL scintillation vials.
Analytical Procedure
A portion of each separate phase is analyzed by gross examination, phase-polar examination, and central stop dispersion microscopy.
Commercial manufacturers and products
mentioned in this method are for descriptive
use only and do not constitute endorsements
by USDOL-OSHA. Similar products from
other sources may be substituted.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
1. Introduction
This method describes the collection and
analysis of asbestos bulk materials by light
microscopy techniques including phasepolar illumination and central-stop dispersion microscopy. Some terms unique to asbestos analysis are defined below:
Amphibole: A family of minerals whose
crystals are formed by long, thin units which
have two thin ribbons of double chain silicate with a brucite ribbon in between. The
shape of each unit is similar to an ‘‘I beam’’.
Minerals important in asbestos analysis include cummingtonite-grunerite, crocidolite,
tremolite- actinolite and anthophyllite.
Asbestos: A term for naturally occurring fibrous minerals. Asbestos includes chrysotile,
cummingtonite-grunerite asbestos (amosite),
anthophyllite asbestos, tremolite asbestos,
crocidolite, actinolite asbestos and any of
these minerals which have been chemically
treated or altered. The precise chemical formulation of each species varies with the location from which it was mined. Nominal
compositions are listed:
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Chrysotile ......
Crocidolite
(Riebeckite
asbestos).
Cummingtonite-Grunerite
asbestos
(Amosite).
Tremolite-Actinolite asbestos.
Anthophyllite
asbestos.
Mg3 Si2 O5(OH)4
Na2Fe32+Fe23+Si8O22(OH)2
(Mg,Fe)7 Si8O22(OH)2
Ca2(Mg,Fe)5Si8O22(OH)2
Phase Contrast: Contrast obtained in the
microscope by causing light scattered by
small particles to destructively interfere
with unscattered light, thereby enhancing
the visibility of very small particles and particles with very low intrinsic contrast.
Phase Contrast Microscope: A microscope
configured with a phase mask pair to create
phase contrast. The technique which uses
this is called Phase Contrast Microscopy
(PCM).
Phase-Polar Analysis: This is the use of polarized light in a phase contrast microscope.
It is used to see the same size fibers that are
visible in air filter analysis. Although fibers
finer than 1 μm are visible, analysis of these
is inferred from analysis of larger bundles
that are usually present.
Phase-Polar Microscope: The phase-polar
microscope is a phase contrast microscope
which has an analyzer, a polarizer, a first
order red plate and a rotating phase condenser all in place so that the polarized light
image is enhanced by phase contrast.
Sealing Encapsulant: This is a product
which can be applied, preferably by spraying,
onto an asbestos surface which will seal the
surface so that fibers cannot be released.
Serpentine: A mineral family consisting of
minerals with the general composition
Mg3(Si2O5(OH)4 having the magnesium in
brucite layer over a silicate layer. Minerals
important in asbestos analysis included in
this
family
are
chrysotile,
lizardite,
antigorite.
(Mg,Fe)7 Si8O22(OH)2
1.1. History
Asbestos Fiber: A fiber of asbestos meeting
the criteria for a fiber. (See section 3.5.)
Aspect Ratio: The ratio of the length of a
fiber to its diameter usually defined as
‘‘length : width’’, e.g. 3:1.
Brucite: A sheet mineral with the composition Mg(OH)2.
Central Stop Dispersion Staining (microscope):
This is a dark field microscope technique
that images particles using only light refracted by the particle, excluding light that
travels through the particle unrefracted.
This is usually accomplished with a McCrone
objective or other arrangement which places
a circular stop with apparent aperture equal
to the objective aperture in the back focal
plane of the microscope.
Cleavage Fragments: Mineral particles
formed by the comminution of minerals, especially those characterized by relatively
parallel sides and moderate aspect ratio.
Differential Counting: The term applied to
the practice of excluding certain kinds of fibers from a phase contrast asbestos count
because they are not asbestos.
Fiber: A particle longer than or equal to 5
μm with a length to width ratio greater than
or equal to 3:1. This may include cleavage
fragments. (see section 3.5 of this appendix).
Light microscopy has been used for well
over 100 years for the determination of mineral species. This analysis is carried out
using specialized polarizing microscopes as
well as bright field microscopes. The identification of minerals is an on-going process
with many new minerals described each
year. The first recorded use of asbestos was
in Finland about 2500 B.C. where the material was used in the mud wattle for the wooden huts the people lived in as well as
strengthening for pottery. Adverse health aspects of the mineral were noted nearly 2000
years ago when Pliny the Younger wrote
about the poor health of slaves in the asbestos mines. Although known to be injurious
for centuries, the first modern references to
its toxicity were by the British Labor
Inspectorate when it banned asbestos dust
from the workplace in 1898. Asbestosis cases
were described in the literature after the
turn of the century. Cancer was first suspected in the mid 1930’s and a causal link to
mesothelioma was made in 1965. Because of
the public concern for worker and public
safety with the use of this material, several
different types of analysis were applied to
the determination of asbestos content. Light
microscopy requires a great deal of experience and craft. Attempts were made to apply
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Occupational Safety and Health Admin., Labor
less subjective methods to the analysis. Xray diffraction was partially successful in
determining the mineral types but was unable to separate out the fibrous portions
from the non-fibrous portions. Also, the minimum detection limit for asbestos analysis
by X-ray diffraction (XRD) is about 1%. Differential Thermal Analysis (DTA) was no
more successful. These provide useful corroborating information when the presence of
asbestos has been shown by microscopy;
however, neither can determine the difference between fibrous and non-fibrous minerals when both habits are present. The same
is true of Infrared Absorption (IR).
When electron microscopy was applied to
asbestos analysis, hundreds of fibers were
discovered present too small to be visible in
any light microscope. There are two different types of electron microscope used for
asbestos analysis: Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Scanning Electron Microscopy is useful in identifying minerals. The
SEM can provide two of the three pieces of
information required to identify fibers by
electron microscopy: morphology and chemistry. The third is structure as determined
by Selected Area Electron Diffraction—
SAED which is performed in the TEM. Although the resolution of the SEM is sufficient for very fine fibers to be seen, accuracy
of chemical analysis that can be performed
on the fibers varies with fiber diameter in fibers of less than 0.2 μm diameter. The TEM
is a powerful tool to identify fibers too small
to be resolved by light microscopy and
should be used in conjunction with this
method when necessary. The TEM can provide all three pieces of information required
for fiber identification. Most fibers thicker
than 1 μm can adequately be defined in the
light microscope. The light microscope remains as the best instrument for the determination of mineral type. This is because
the minerals under investigation were first
described analytically with the light microscope. It is inexpensive and gives positive
identification for most samples analyzed.
Further, when optical techniques are inadequate, there is ample indication that alternative techniques should be used for complete identification of the sample.
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1.2. Principle
Minerals consist of atoms that may be arranged in random order or in a regular arrangement. Amorphous materials have
atoms in random order while crystalline materials have long range order. Many materials are transparent to light, at least for
small particles or for thin sections. The
properties of these materials can be investigated by the effect that the material has
on light passing through it. The six asbestos
minerals are all crystalline with particular
§ 1915.1001
properties that have been identified and cataloged. These six minerals are anisotropic.
They have a regular array of atoms, but the
arrangement is not the same in all directions. Each major direction of the crystal
presents a different regularity. Light photons travelling in each of these main directions will encounter different electrical
neighborhoods, affecting the path and time
of travel. The techniques outlined in this
method use the fact that light traveling
through fibers or crystals in different directions will behave differently, but predictably. The behavior of the light as it travels
through a crystal can be measured and compared with known or determined values to
identify the mineral species. Usually, Polarized Light Microscopy (PLM) is performed
with strain-free objectives on a bright-field
microscope platform. This would limit the
resolution of the microscope to about 0.4 μm.
Because OSHA requires the counting and
identification of fibers visible in phase contrast, the phase contrast platform is used to
visualize the fibers with the polarizing elements added into the light path. Polarized
light methods cannot identify fibers finer
than about 1μm in diameter even though
they are visible. The finest fibers are usually
identified by inference from the presence of
larger, identifiable fiber bundles. When fibers
are present, but not identifiable by light microscopy, use either SEM or TEM to determine the fiber identity.
1.3. Advantages and Disadvantages
The advantages of light microcopy are:
(a) Basic identification of the materials
was first performed by light microscopy and
gross analysis. This provides a large base of
published information against which to
check analysis and analytical technique.
(b) The analysis is specific to fibers. The
minerals present can exist in asbestiform, fibrous, prismatic, or massive varieties all at
the same time. Therefore, bulk methods of
analysis such as X-ray diffraction, IR analysis, DTA, etc. are inappropriate where the
material is not known to be fibrous.
(c) The analysis is quick, requires little
preparation time, and can be performed onsite if a suitably equipped microscope is
available.
The disadvantages are:
(a) Even using phase-polar illumination,
not all the fibers present may be seen. This
is a problem for very low asbestos concentrations where agglomerations or large bundles
of fibers may not be present to allow identification by inference.
(b) The method requires a great degree of
sophistication
on
the
part
of
the
microscopist. An analyst is only as useful as
his mental catalog of images. Therefore, a
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
microscopist’s accuracy is enhanced by experience. The mineralogical training of the analyst is very important. It is the basis on
which subjective decisions are made.
(c) The method uses only a tiny amount of
material for analysis. This may lead to sampling bias and false results (high or low).
This is especially true if the sample is severely inhomogeneous.
(d) Fibers may be bound in a matrix and
not distinguishable as fibers so identification cannot be made.
1.4. Method Performance
1.4.1. This method can be used for determination of asbestos content from 0 to 100%
asbestos. The detection limit has not been
adequately determined, although for selected
samples, the limit is very low, depending on
the number of particles examined. For mostly homogeneous, finely divided samples, with
no difficult fibrous interferences, the detection limit is below 1%. For inhomogeneous
samples (most samples), the detection limit
remains undefined. NIST has conducted proficiency testing of laboratories on a national
scale. Although each round is reported statistically with an average, control limits,
etc., the results indicate a difficulty in establishing precision especially in the low
concentration range. It is suspected that
there is significant bias in the low range especially near 1%. EPA tried to remedy this
by requiring a mandatory point counting
scheme for samples less than 10%. The point
counting procedure is tedious, and may introduce significant biases of its own. It has
not been incorporated into this method.
1.4.2. The precision and accuracy of the
quantitation tests performed in this method
are unknown. Concentrations are easier to
determine in commercial products where asbestos was deliberately added because the
amount is usually more than a few percent.
An analyst’s results can be ‘‘calibrated’’
against the known amounts added by the
manufacturer. For geological samples, the
degree of homogeneity affects the precision.
1.4.3. The performance of the method is analyst dependent. The analyst must choose
carefully and not necessarily randomly the
portions for analysis to assure that detection
of asbestos occurs when it is present. For
this reason, the analyst must have adequate
training in sample preparation, and experience in the location and identification of asbestos in samples. This is usually accomplished through substantial on-the-job training as well as formal education in mineralogy and microscopy.
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1.5. Interferences
Any material which is long, thin, and
small enough to be viewed under the microscope can be considered an interference for
asbestos. There are literally hundreds of
interferences in workplaces. The techniques
described in this method are normally sufficient to eliminate the interferences. An analyst’s success in eliminating the interferences depends on proper training.
Asbestos minerals belong to two mineral
families: the serpentines and the amphiboles.
In the serpentine family, the only common
fibrous mineral is chrysotile. Occasionally,
the mineral antigorite occurs in a fibril
habit with morphology similar to the
amphiboles. The amphibole minerals consist
of a score of different minerals of which only
five are regulated by federal standard:
amosite, crocidolite, anthophyllite asbestos,
tremolite asbestos and actinolite asbestos.
These are the only amphibole minerals that
have been commercially exploited for their
fibrous properties; however, the rest can and
do occur occasionally in asbestiform habit.
In addition to the related mineral interferences, other minerals common in building
material may present a problem for some
microscopists: gypsum, anhydrite, brucite,
quartz fibers, talc fibers or ribbons, wollastonite, perlite, attapulgite, etc. Other fibrous materials commonly present in workplaces are: fiberglass, mineral wool, ceramic
wool, refractory ceramic fibers, kevlar,
nomex, synthetic fibers, graphite or carbon
fibers, cellulose (paper or wood) fibers, metal
fibers, etc.
Matrix embedding material can sometimes
be a negative interference. The analyst may
not be able to easily extract the fibers from
the matrix in order to use the method.
Where possible, remove the matrix before
the analysis, taking careful note of the loss
of weight. Some common matrix materials
are: vinyl, rubber, tar, paint, plant fiber, cement, and epoxy. A further negative interference is that the asbestos fibers themselves
may be either too small to be seen in Phase
contrast Microscopy (PCM) or of a very low
fibrous quality, having the appearance of
plant fibers. The analyst’s ability to deal
with these materials increases with experience.
1.6. Uses and Occupational Exposure
Asbestos is ubiquitous in the environment.
More than 40% of the land area of the United
States is composed of minerals which may
contain asbestos. Fortunately, the actual
formation of great amounts of asbestos is
relatively rare. Nonetheless, there are locations in which environmental exposure can
be severe such as in the Serpentine Hills of
California.
There are thousands of uses for asbestos in
industry and the home. Asbestos abatement
workers are the most current segment of the
population to have occupational exposure to
great amounts of asbestos. If the material is
undisturbed, there is no exposure. Exposure
occurs when the asbestos-containing material is abraded or otherwise disturbed during
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Occupational Safety and Health Admin., Labor
maintenance operations or some other activity. Approximately 95% of the asbestos in
place in the United States is chrysotile.
Amosite and crocidolite make up nearly
all
the
difference.
Tremolite
and
anthophyllite make up a very small percentage. Tremolite is found in extremely small
amounts in certain chrysotile deposits. Actinolite exposure is probably greatest from
environmental sources, but has been identified in vermiculite containing, sprayed-on
insulating materials which may have been
certified as asbestos-free.
1.7. Physical and Chemical Properties
The nominal chemical compositions for
the asbestos minerals were given in Section
1. Compared to cleavage fragments of the
same minerals, asbestiform fibers possess a
high tensile strength along the fiber axis.
They are chemically inert, non-combustible,
and heat resistant. Except for chrysotile,
they are insoluble in Hydrochloric acid
(HCl). Chrysotile is slightly soluble in HCl.
Asbestos has high electrical resistance and
good sound absorbing characteristics. It can
be woven into cables, fabrics or other textiles, or matted into papers, felts, and mats.
1.8. Toxicology (This Section is for Information Only and Should Not Be Taken as
OSHA Policy)
§ 1915.1001
2.3. Sampling procedure
Samples of any suspect material should be
taken from an inconspicuous place. Where
the material is to remain, seal the sampling
wound with an encapsulant to eliminate the
potential for exposure from the sample site.
Microscopy requires only a few milligrams of
material. The amount that will fill a 20 mL
scintillation vial is more than adequate. Be
sure to collect samples from all layers and
phases of material. If possible, make separate samples of each different phase of the
material. This will aid in determining the
actual hazard. DO NOT USE ENVELOPES,
PLASTIC OR PAPER BAGS OF ANY KIND TO
COLLECT SAMPLES. The use of plastic bags
presents a contamination hazard to laboratory personnel and to other samples. When
these containers are opened, a bellows effect
blows fibers out of the container onto everything, including the person opening the container.
If a cork-borer type sampler is available,
push the tube through the material all the
way, so that all layers of material are sampled. Some samplers are intended to be disposable. These should be capped and sent to
the laboratory. If a non-disposable cork
borer is used, empty the contents into a scintillation vial and send to the laboratory.
Vigorously and completely clean the cork
borer between samples.
2.4 Shipment
Possible physiologic results of respiratory
exposure to asbestos are mesothelioma of the
pleura or peritoneum, interstitial fibrosis,
asbestosis, pneumoconiosis, or respiratory
cancer. The possible consequences of asbestos exposure are detailed in the NIOSH Criteria Document or in the OSHA Asbestos
Standards 29 CFR 1910.1001 and 29 CFR
1926.1101 and 29 CFR 1915.1001.
2. Sampling Procedure
2.1. Equipment for Sampling
(a)
(b)
(c)
(d)
Tube or cork borer sampling device
Knife
20 mL scintillation vial or similar vial
Sealing encapsulant
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2.2. Safety Precautions
Asbestos is a known carcinogen. Take care
when sampling. While in an asbestos-containing atmosphere, a properly selected and
fit-tested respirator should be worn. Take
samples in a manner to cause the least
amount of dust. Follow these general guidelines:
(a) Do not make unnecessary dust.
(b) Take only a small amount (1 to 2 g).
(c) Tightly close the sample container.
(d) Use encapsulant to seal the spot where
the sample was taken, if necessary.
Samples packed in glass vials must not
touch or they might break in shipment.
(a) Seal the samples with a sample seal
over the end to guard against tampering and
to identify the sample.
(b) Package the bulk samples in separate
packages from the air samples. They may
cross-contaminate each other and will invalidate the results of the air samples.
(c) Include identifying paperwork with the
samples, but not in contact with the suspected asbestos.
(d) To maintain sample accountability,
ship the samples by certified mail, overnight
express, or hand carry them to the laboratory.
3. Analysis
The analysis of asbestos samples can be divided into two major parts: sample preparation and microscopy. Because of the different
asbestos uses that may be encountered by
the analyst, each sample may need different
preparation steps. The choices are outlined
below. There are several different tests that
are performed to identify the asbestos species and determine the percentage. They will
be explained below.
3.1. Safety
(a) Do not create unnecessary dust. Handle
the samples in HEPA-filter equipped hoods.
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
If samples are received in bags, envelopes or
other inappropriate container, open them
only in a hood having a face velocity at or
greater than 100 fpm. Transfer a small
amount to a scintillation vial and only handle the smaller amount.
(b) Open samples in a hood, never in the
open lab area.
(c) Index of refraction oils can be toxic.
Take care not to get this material on the
skin. Wash immediately with soap and water
if this happens.
(d) Samples that have been heated in the
muffle furnace or the drying oven may be
hot. Handle them with tongs until they are
cool enough to handle.
(e) Some of the solvents used, such as THF
(tetrahydrofuran), are toxic and should only
be handled in an appropriate fume hood and
according to instructions given in the safety
data sheet (SDS).
Sodium Potassium Tartrate .........8.0 mg/liter
Hydrochloric Acid ..........................99.2 g/liter
Sodium Tartrate.............................0.14 g/liter
(q) Tetrahydrofuran (THF)
(r) Hotplate capable of 60 °C
(s) Balance
(t) Hacksaw blade
(u) Ruby mortar and pestle
3.3. Sample Pre-Preparation
Sample preparation begins with pre-preparation which may include chemical reduction of the matrix, heating the sample to
dryness or heating in the muffle furnace. The
end result is a sample which has been reduced to a powder that is sufficiently fine to
fit under the cover slip. Analyze different
phases of samples separately, e.g., tile and
the tile mastic should be analyzed separately
as the mastic may contain asbestos while
the tile may not.
3.2. Equipment
(a) Wet Samples
(a) Phase contrast microscope with 10x, 16x
and 40x objectives, 10x wide-field eyepieces,
G–22 Walton-Beckett graticule, Whipple
disk, polarizer, analyzer and first order red
or gypsum plate, 100 Watt illuminator, rotating position condenser with oversize phase
rings, central stop dispersion objective,
Kohler
illumination
and
a
rotating
mechanicalstage. (See figure 1).
(b) Stereo microscope with reflected light
illumination, transmitted light illumination, polarizer, analyzer and first order red
or gypsum plate, and rotating stage.
(c) Negative pressure hood for the stereo
microscope
(d) Muffle furnace capable of 600 °C
(e) Drying oven capable of 50–150 °C
(f) Aluminum specimen pans
(g) Tongs for handling samples in the furnace
(h) High dispersion index of refraction oils
(Special for dispersion staining.)
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n
n
n
n
n
n
n
n
=
=
=
=
=
=
=
=
1.550
1.585
1.590
1.605
1.620
1.670
1.680
1.690
(i) A set of index of refraction oils from
about n=1.350 to n=2.000 in n=0.005 increments. (Standard for Becke line analysis.)
(j) Glass slides with painted or frosted ends
1×3 inches 1mm thick, precleaned.
(k) Cover Slips 22×22 mm, #11⁄2
(l) Paper clips or dissection needles
(m) Hand grinder
(n) Scalpel with both #10 and #11 blades
(o) 0.1 molar HCl
(p) Decalcifying solution (Baxter Scientific
Products) Ethylenediaminetetraacetic Acid,
Tetrasodium ..........................................0.7 g/l
Samples with a high water content will not
give the proper dispersion colors and must be
dried prior to sample mounting. Remove the
lid of the scintillation vial, place the bottle
in the drying oven and heat at 100 °C to dryness (usually about 2 h). Samples which are
not submitted to the lab in glass must be removed and placed in glass vials or aluminum
weighing pans before placing them in the
drying oven.
(b) Samples With Organic Interference—
Muffle Furnace
These may include samples with tar as a
matrix, vinyl asbestos tile, or any other organic that can be reduced by heating. Remove the sample from the vial and weigh in
a balance to determine the weight of the submitted portion. Place the sample in a muffle
furnace at 500 °C for 1 to 2 h or until all obvious organic material has been removed. Retrieve, cool and weigh again to determine
the weight loss on ignition. This is necessary
to determine the asbestos content of the submitted sample, because the analyst will be
looking at a reduced sample.
NOTES: Heating above 600 °C will cause the
sample to undergo a structural change
which, given sufficient time, will convert the
chrysotile to forsterite. Heating even at
lower temperatures for 1 to 2 h may have a
measurable effect on the optical properties
of the minerals. If the analyst is unsure of
what to expect, a sample of standard asbestos should be heated to the same temperature for the same length of time so that it
can be examined for the proper interpretation.
(c) Samples With Organic Interference—THF
Vinyl asbestos tile is the most common
material treated with this solvent, although,
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31
Occupational Safety and Health Admin., Labor
substances containing tar will sometimes
yield to this treatment. Select a portion of
the material and then grind it up if possible.
Weigh the sample and place it in a test tube.
Add sufficient THF to dissolve the organic
matrix. This is usually about 4 to 5 mL. Remember, THF is highly flammable. Filter the
remaining material through a tared silver
membrane, dry and weigh to determine how
much is left after the solvent extraction.
Further process the sample to remove carbonate or mount directly.
(d) Samples With Carbonate Interference
Carbonate material is often found on fibers
and sometimes must be removed in order to
perform dispersion microscopy. Weigh out a
portion of the material and place it in a test
tube. Add a sufficient amount of 0.1 M HCl or
decalcifying solution in the tube to react all
the carbonate as evidenced by gas formation;
i.e., when the gas bubbles stop, add a little
more solution. If no more gas forms, the reaction is complete. Filter the material out
through a tared silver membrane, dry and
weigh to determine the weight lost.
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3.4. Sample Preparation
Samples must be prepared so that accurate
determination can be made of the asbestos
type and amount present. The following
steps are carried out in the low-flow hood (a
low-flow hood has less than 50 fpm flow):
(1) If the sample has large lumps, is hard,
or cannot be made to lie under a cover slip,
the grain size must be reduced. Place a small
amount between two slides and grind the
material between them or grind a small
amount in a clean mortar and pestle. The
choice of whether to use an alumina, ruby,
or diamond mortar depends on the hardness
of the material. Impact damage can alter the
asbestos mineral if too much mechanical
shock occurs. (Freezer mills can completely
destroy the observable crystallinity of asbestos and should not be used). For some samples, a portion of material can be shaved off
with a scalpel, ground off with a hand grinder or hack saw blade.
The preparation tools should either be disposable or cleaned thoroughly. Use vigorous
scrubbing to loosen the fibers during the
washing. Rinse the implements with copious
amounts of water and air-dry in a dust-free
environment.
(2) If the sample is powder or has been reduced as in 1) above, it is ready to mount.
Place a glass slide on a piece of optical tissue and write the identification on the painted or frosted end. Place two drops of index of
refraction medium n=1.550 on the slide. (The
medium n=1.550 is chosen because it is the
matching index for chrysotile. Dip the end of
a clean paper-clip or dissecting needle into
the droplet of refraction medium on the slide
to moisten it. Then dip the probe into the
§ 1915.1001
powder sample. Transfer what sticks on the
probe to the slide. The material on the end of
the probe should have a diameter of about 3
mm for a good mount. If the material is very
fine, less sample may be appropriate. For
non-powder samples such as fiber mats, forceps should be used to transfer a small
amount of material to the slide. Stir the material in the medium on the slide, spreading
it out and making the preparation as uniform as possible. Place a cover-slip on the
preparation by gently lowering onto the
slide and allowing it to fall ‘‘trapdoor’’ fashion on the preparation to push out any bubbles. Press gently on the cover slip to even
out the distribution of particulate on the
slide. If there is insufficient mounting oil on
the slide, one or two drops may be placed
near the edge of the coverslip on the slide.
Capillary action will draw the necessary
amount of liquid into the preparation. Remove excess oil with the point of a laboratory wiper.
Treat at least two different areas of each
phase in this fashion. Choose representative
areas of the sample. It may be useful to select particular areas or fibers for analysis.
This is useful to identify asbestos in severely
inhomogeneous samples.
When it is determined that amphiboles
may be present, repeat the above process
using the appropriate high- dispersion oils
until an identification is made or all six asbestos minerals have been ruled out. Note
that percent determination must be done in
the index medium 1.550 because amphiboles
tend to disappear in their matching mediums.
3.5. Analytical procedure
NOTE: This method presumes some knowledge of mineralogy and optical petrography.
The analysis consists of three parts: The
determination of whether there is asbestos
present, what type is present and the determination of how much is present. The general flow of the analysis is:
(1) Gross examination.
(2) Examination under polarized light on
the stereo microscope.
(3) Examination by phase-polar illumination on the compound phase microscope.
(4) Determination of species by dispersion
stain. Examination by Becke line analysis
may also be used; however, this is usually
more cumbersome for asbestos determination.
(5) Difficult samples may need to be analyzed by SEM or TEM, or the results from
those techniques combined with light microscopy for a definitive identification. Identification of a particle as asbestos requires
that it be asbestiform. Description of particles should follow the suggestion of Campbell. (Figure 1)
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29 CFR Ch. XVII (7–1–15 Edition)
For the purpose of regulation, the mineral
must be one of the six minerals covered and
must be in the asbestos growth habit. Large
specimen samples of asbestos generally have
the gross appearance of wood. Fibers are easily parted from it. Asbestos fibers are very
long compared with their widths. The fibers
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ER10AU94.024
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§ 1915.1001
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Occupational Safety and Health Admin., Labor
have a very high tensile strength as demonstrated by bending without breaking. Asbestos fibers exist in bundles that are easily
parted, show longitudinal fine structure and
may be tufted at the ends showing ‘‘bundle
of sticks’’ morphology. In the microscope
some of these properties may not be observable. Amphiboles do not always show striations along their length even when they are
asbestos. Neither will they always show tufting. They generally do not show a curved nature except for very long fibers. Asbestos and
asbestiform minerals are usually characterized in groups by extremely high aspect ratios (greater than 100:1). While aspect ratio
analysis is useful for characterizing populations of fibers, it cannot be used to identify
individual fibers of intermediate to short aspect ratio. Observation of many fibers is
often necessary to determine whether a sample consists of ‘‘cleavage fragments’’ or of asbestos fibers.
Most cleavage fragments of the asbestos
minerals are easily distinguishable from true
asbestos fibers. This is because true cleavage
fragments usually have larger diameters
than 1 μm. Internal structure of particles
larger than this usually shows them to have
no internal fibrillar structure. In addition,
cleavage fragments of the monoclinic
amphiboles show inclined extinction under
crossed polars with no compensator. Asbestos fibers usually show extinction at zero degrees or ambiguous extinction if any at all.
Morphologically, the larger cleavage fragments are obvious by their blunt or stepped
ends showing prismatic habit. Also, they
tend to be acicular rather than filiform.
Where the particles are less than 1 μm in
diameter and have an aspect ratio greater
than or equal to 3:1, it is recommended that
the sample be analyzed by SEM or TEM if
there is any question whether the fibers are
cleavage fragments or asbestiform particles.
Care must be taken when analyzing by
electron microscopy because the interferences are different from those in light microscopy and may structurally be very similar to asbestos. The classic interference is
between anthophyllite and biopyribole or intermediate fiber. Use the same morphological clues for electron microscopy as are
used for light microscopy, e.g. fibril splitting, internal longitudinal striation, fraying,
curvature, etc.
(1) Gross examination:
Examine the sample, preferably in the
glass vial. Determine the presence of any obvious fibrous component. Estimate a percentage based on previous experience and
current observation. Determine whether any
pre-preparation is necessary. Determine the
number of phases present. This step may be
carried out or augmented by observation at
6 to 40× under a stereo microscope.
(2) After performing any necessary prepreparation, prepare slides of each phase as
§ 1915.1001
described above. Two preparations of the
same phase in the same index medium can be
made side-by-side on the same glass for convenience. Examine with the polarizing stereo
microscope. Estimate the percentage of asbestos based on the amount of birefringent
fiber present.
(3) Examine the slides on the phase-polar
microscopes at magnifications of 160 and
400×. Note the morphology of the fibers.
Long, thin, very straight fibers with little
curvature are indicative of fibers from the
amphibole family. Curved, wavy fibers are
usually indicative of chrysotile. Estimate
the percentage of asbestos on the phase-polar
microscope under conditions of crossed
polars and a gypsum plate. Fibers smaller
than 1.0 μm in thickness must be identified
by inference to the presence of larger, identifiable fibers and morphology. If no larger fibers are visible, electron microscopy should
be performed. At this point, only a tentative
identification can be made. Full identification must be made with dispersion microscopy. Details of the tests are included in the
appendices.
(4) Once fibers have been determined to be
present, they must be identified. Adjust the
microscope for dispersion mode and observe
the fibers. The microscope has a rotating
stage, one polarizing element, and a system
for generating dark-field dispersion microscopy (see Section 4.6. of this appendix). Align
a fiber with its length parallel to the polarizer and note the color of the Becke lines.
Rotate the stage to bring the fiber length
perpendicular to the polarizer and note the
color. Repeat this process for every fiber or
fiber bundle examined. The colors must be
consistent with the colors generated by
standard asbestos reference materials for a
positive
identification.
In
n=1.550,
amphiboles will generally show a yellow to
straw-yellow color indicating that the fiber
indices of refraction are higher than the liquid. If long, thin fibers are noted and the colors are yellow, prepare further slides as
above in the suggested matching liquids listed below:
Type of asbestos
Chrysotile ...............................
Amosite ..................................
Crocidolite ..............................
Anthophyllite ..........................
Tremolite ................................
Actinolite ................................
Index of refraction
n=1.550.
n=1.670 or 1.680.
n=1.690.
n=1.605 and 1.620.
n=1.605 and 1.620.
n=1.620.
Where more than one liquid is suggested,
the first is preferred; however, in some cases
this liquid will not give good dispersion
color. Take care to avoid interferences in the
other liquid; e.g., wollastonite in n=1.620 will
give the same colors as tremolite. In n=1.605
wollastonite will appear yellow in all directions. Wollastonite may be determined under
crossed polars as it will change from blue to
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
yellow as it is rotated along its fiber axis by
tapping on the cover slip. Asbestos minerals
will not change in this way.
Determination of the angle of extinction
may, when present, aid in the determination
of anthophyllite from tremolite. True asbestos fibers usually have 0° extinction or ambiguous extinction, while cleavage fragments
have more definite extinction.
Continue analysis until both preparations
have been examined and all present species
of asbestos are identified. If there are no fibers present, or there is less than 0.1%
present, end the analysis with the minimum
number of slides (2).
(5) Some fibers have a coating on them
which makes dispersion microscopy very difficult or impossible. Becke line analysis or
electron microscopy may be performed in
those cases. Determine the percentage by
light microscopy. TEM analysis tends to
overestimate the actual percentage present.
(6) Percentage determination is an estimate of occluded area, tempered by gross observation. Gross observation information is
used to make sure that the high magnification microscopy does not greatly over- or
under-estimate the amount of fiber present.
This part of the analysis requires a great
deal of experience. Satisfactory models for
asbestos content analysis have not yet been
developed, although some models based on
metallurgical grain-size determination have
found some utility. Estimation is more easily handled in situations where the grain
sizes visible at about 160× are about the same
and the sample is relatively homogeneous.
View all of the area under the cover slip to
make the percentage determination. View
the fields while moving the stage, paying attention to the clumps of material. These are
not usually the best areas to perform dispersion microscopy because of the interference
from other materials. But, they are the areas
most likely to represent the accurate percentage in the sample. Small amounts of asbestos require slower scanning and more frequent analysis of individual fields.
Report the area occluded by asbestos as
the concentration. This estimate does not
generally take into consideration the difference in density of the different species
present in the sample. For most samples this
is adequate. Simulation studies with similar
materials must be carried out to apply
microvisual estimation for that purpose and
is beyond the scope of this procedure.
(7) Where successive concentrations have
been made by chemical or physical means,
the amount reported is the percentage of the
material in the ‘‘as submitted’’ or original
state. The percentage determined by microscopy is multiplied by the fractions remaining after pre-preparation steps to give the
percentage in the original sample. For example:
Step 1. 60% remains after heating at 550 °C
for 1 h.
Step 2. 30% of the residue of step 1 remains
after dissolution of carbonate in 0.1 m HCl.
Step 3. Microvisual estimation determines
that 5% of the sample is chrysotile asbestos.
The reported result is:
R = (Microvisual result in percent)×(Fraction
remaining after step 2)×(Fraction remaining of original sample after step 1)
R = (5)×(.30)×(.60) = 0.9%
(8) Report the percent and type of asbestos
present. For samples where asbestos was
identified, but is less than 1.0%, report ‘‘Asbestos present, less than 1.0%.’’ There must
have been at least two observed fibers or
fiber bundles in the two preparations to be
reported as present. For samples where asbestos was not seen, report as ‘‘None Detected.’’
4. Auxiliary Information
Because of the subjective nature of asbestos analysis, certain concepts and procedures
need to be discussed in more depth. This information will help the analyst understand
why some of the procedures are carried out
the way they are.
4.1. Light
Light is electromagnetic energy. It travels
from its source in packets called quanta. It
is instructive to consider light as a plane
wave. The light has a direction of travel.
Perpendicular to this and mutually perpendicular to each other, are two vector components. One is the magnetic vector and the
other is the electric vector. We shall only be
concerned with the electric vector. In this
description, the interaction of the vector and
the mineral will describe all the observable
phenomena. From a light source such a microscope illuminator, light travels in all different direction from the filament.
In any given direction away from the filament, the electric vector is perpendicular to
the direction of travel of a light ray. While
perpendicular, its orientation is random
about the travel axis. If the electric vectors
from all the light rays were lined up by passing the light through a filter that would only
let light rays with electric vectors oriented
in one direction pass, the light would then be
POLARIZED.
Polarized light interacts with matter in
the direction of the electric vector. This is
the polarization direction. Using this property it is possible to use polarized light to
probe different materials and identify them
by how they interact with light. The speed of
light in a vacuum is a constant at about
2.99×10 8 m/s. When light travels in different
materials such as air, water, minerals or oil,
it does not travel at this speed. It travels
slower. This slowing is a function of both the
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Occupational Safety and Health Admin., Labor
material through which the light is traveling
and the wavelength or frequency of the light.
In general, the more dense the material, the
slower the light travels. Also, generally, the
higher the frequency, the slower the light
will travel. The ratio of the speed of light in
a vacuum to that in a material is called the
index of refraction (n). It is usually measured at 589 nm (the sodium D line). If white
light (light containing all the visible wavelengths) travels through a material, rays of
longer wavelengths will travel faster than
those of shorter wavelengths, this separation
is called dispersion. Dispersion is used as an
identifier of materials as described in Section 4.6.
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4.2. Material Properties
Materials are either amorphous or crystalline. The difference between these two descriptions depends on the positions of the
atoms in them. The atoms in amorphous materials are randomly arranged with no long
range order. An example of an amorphous
material is glass. The atoms in crystalline
materials, on the other hand, are in regular
arrays and have long range order. Most of
the atoms can be found in highly predictable
locations. Examples of crystalline material
are salt, gold, and the asbestos minerals.
It is beyond the scope of this method to describe the different types of crystalline materials that can be found, or the full description of the classes into which they can fall.
However, some general crystallography is
provided below to give a foundation to the
procedures described.
With the exception of anthophyllite, all
the asbestos minerals belong to the
monoclinic crystal type. The unit cell is the
basic repeating unit of the crystal and for
monoclinic crystals can be described as having three unequal sides, two 90° angles and
one angle not equal to 90°. The orthorhombic
group, of which anthophyllite is a member
has three unequal sides and three 90° angles.
The unequal sides are a consequence of the
complexity of fitting the different atoms
into the unit cell. Although the atoms are in
a regular array, that array is not symmetrical in all directions. There is long range
order in the three major directions of the
crystal. However, the order is different in
each of the three directions. This has the effect that the index of refraction is different
in each of the three directions. Using polarized light, we can investigate the index of refraction in each of the directions and identify the mineral or material under investigation. The indices a, b, and g are used to identify the lowest, middle, and highest index of
refraction respectively. The x direction, associated with a is called the fast axis. Conversely, the z direction is associated with g
and is the slow direction. Crocidolite has a
along the fiber length making it ‘‘length-
§ 1915.1001
fast’’. The remainder of the asbestos minerals have the g axis along the fiber length.
They are called ‘‘length-slow’’. This orientation to fiber length is used to aid in the identification of asbestos.
4.3. Polarized Light Technique
Polarized light microscopy as described in
this section uses the phase-polar microscope
described in Section 3.2. A phase contrast
microscope is fitted with two polarizing elements, one below and one above the sample.
The polarizers have their polarization directions at right angles to each other. Depending on the tests performed, there may be a
compensator between these two polarizing
elements. Light emerging from a polarizing
element has its electric vector pointing in
the polarization direction of the element.
The light will not be subsequently transmitted through a second element set at a
right angle to the first element. Unless the
light is altered as it passes from one element
to the other, there is no transmission of
light.
4.4. Angle of Extinction
Crystals which have different crystal regularity in two or three main directions are
said to be anisotropic. They have a different
index of refraction in each of the main directions. When such a crystal is inserted between the crossed polars, the field of view is
no longer dark but shows the crystal in
color. The color depends on the properties of
the crystal. The light acts as if it travels
through the crystal along the optical axes. If
a crystal optical axis were lined up along one
of the polarizing directions (either the polarizer or the analyzer) the light would appear
to travel only in that direction, and it would
blink out or go dark. The difference in degrees between the fiber direction and the
angle at which it blinks out is called the
angle of extinction. When this angle can be
measured, it is useful in identifying the mineral. The procedure for measuring the angle
of extinction is to first identify the polarization direction in the microscope. A commercial alignment slide can be used to establish
the
polarization
directions
or
use
anthophyllite or another suitable mineral.
This mineral has a zero degree angle of extinction and will go dark to extinction as it
aligns with the polarization directions. When
a fiber of anthophyllite has gone to extinction, align the eyepiece reticle or graticule
with the fiber so that there is a visual cue as
to the direction of polarization in the field of
view. Tape or otherwise secure the eyepiece
in this position so it will not shift.
After the polarization direction has been
identified in the field of view, move the particle of interest to the center of the field of
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§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
view and align it with the polarization direction. For fibers, align the fiber along this direction. Note the angular reading of the rotating stage. Looking at the particle, rotate
the stage until the fiber goes dark or ‘‘blinks
out’’. Again note the reading of the stage.
The difference in the first reading and the
second is an angle of extinction.
The angle measured may vary as the orientation of the fiber changes about its long
axis. Tables of mineralogical data usually report the maximum angle of extinction. Asbestos forming minerals, when they exhibit
an angle of extinction, usually do show an
angle of extinction close to the reported
maximum, or as appropriate depending on
the substitution chemistry.
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4.5. Crossed Polars With Compensator
When the optical axes of a crystal are not
lined up along one of the polarizing directions (either the polarizer or the analyzer)
part of the light travels along one axis and
part travels along the other visible axis. This
is characteristic of birefringent materials.
The color depends on the difference of the
two visible indices of refraction and the
thickness of the crystal. The maximum difference available is the difference between
the a and the g axes. This maximum difference is usually tabulated as the
birefringence of the crystal.
For this test, align the fiber at 45° to the
polarization directions in order to maximize
the contribution to each of the optical axes.
The colors seen are called retardation colors.
They arise from the recombination of light
which has traveled through the two separate
directions of the crystal. One of the rays is
retarded behind the other since the light in
that direction travels slower. On recombination, some of the colors which make up
white light are enhanced by constructive interference and some are suppressed by destructive interference. The result is a color
dependent on the difference between the indices and the thickness of the crystal. The
proper colors, thicknesses, and retardations
are shown on a Michel-Levy chart. The three
items,
retardation,
thickness
and
birefringence are related by the following relationship:
R = t(nγ—α)
R = retardation, t = crystal thickness in μm,
and
α,γ = indices of refraction.
Examination of the equation for asbestos
minerals reveals that the visible colors for
almost all common asbestos minerals and
fiber sizes are shades of gray and black. The
eye is relatively poor at discriminating different shades of gray. It is very good at discriminating different colors. In order to
compensate for the low retardation, a compensator is added to the light train between
the polarization elements. The compensator
used for this test is a gypsum plate of known
thickness and birefringence. Such a compensator when oriented at 45° to the polarizer direction, provides a retardation of 530 nm of
the 530 nm wavelength color. This enhances
the red color and gives the background a
characteristic red to red-magenta color. If
this ‘‘full-wave’’ compensator is in place
when the asbestos preparation is inserted
into the light train, the colors seen on the fibers are quite different. Gypsum, like asbestos has a fast axis and a slow axis. When a
fiber is aligned with its fast axis in the same
direction as the fast axis of the gypsum
plate, the ray vibrating in the slow direction
is retarded by both the asbestos and the gypsum. This results in a higher retardation
than would be present for either of the two
minerals. The color seen is a second order
blue. When the fiber is rotated 90° using the
rotating stage, the slow direction of the fiber
is now aligned with the fast direction of the
gypsum and the fast direction of the fiber is
aligned with the slow direction of the gypsum. Thus, one ray vibrates faster in the fast
direction of the gypsum, and slower in the
slow direction of the fiber; the other ray will
vibrate slower in the slow direction of the
gypsum and faster in the fast direction of
the fiber. In this case, the effect is subtractive and the color seen is a first order yellow. As long as the fiber thickness does not
add appreciably to the color, the same basic
colors will be seen for all asbestos types except crocidolite. In crocidolite the colors
will be weaker, may be in the opposite directions, and will be altered by the blue absorption color natural to crocidolite. Hundreds of
other materials will give the same colors as
asbestos, and therefore, this test is not definitive for asbestos. The test is useful in discriminating against fiberglass or other
amorphous fibers such as some synthetic fibers. Certain synthetic fibers will show retardation colors different than asbestos;
however, there are some forms of polyethylene and aramid which will show morphology and retardation colors similar to asbestos minerals. This test must be supplemented with a positive identification test
when birefringent fibers are present which
can not be excluded by morphology. This
test is relatively ineffective for use on fibers
less than 1 μm in diameter. For positive confirmation TEM or SEM should be used if no
larger bundles or fibers are visible.
4.6. Dispersion Staining
Dispersion microscopy or dispersion staining is the method of choice for the identification of asbestos in bulk materials. Becke
line analysis is used by some laboratories
and yields the same results as does dispersion staining for asbestos and can be used in
lieu of dispersion staining. Dispersion staining is performed on the same platform as the
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Occupational Safety and Health Admin., Labor
phase-polar analysis with the analyzer and
compensator removed. One polarizing element remains to define the direction of the
light so that the different indices of refraction of the fibers may be separately determined. Dispersion microscopy is a dark-field
technique when used for asbestos. Particles
are imaged with scattered light. Light which
is unscattered is blocked from reaching the
eye either by the back field image mask in a
McCrone objective or a back field image
mask in the phase condenser. The most convenient method is to use the rotating phase
condenser to move an oversized phase ring
into place. The ideal size for this ring is for
the central disk to be just larger than the
objective entry aperture as viewed in the
back focal plane. The larger the disk, the
less scattered light reaches the eye. This will
have the effect of diminishing the intensity
of dispersion color and will shift the actual
color seen. The colors seen vary even on microscopes from the same manufacturer. This
is due to the different bands of wavelength
exclusion by different mask sizes. The mask
may either reside in the condenser or in the
objective back focal plane. It is imperative
that the analyst determine by experimentation with asbestos standards what the appropriate colors should be for each asbestos
type. The colors depend also on the temperature of the preparation and the exact chemistry of the asbestos. Therefore, some slight
differences from the standards should be allowed. This is not a serious problem for commercial asbestos uses. This technique is used
for identification of the indices of refraction
for fibers by recognition of color. There is no
direct numerical readout of the index of refraction. Correlation of color to actual index
of refraction is possible by referral to published conversion tables. This is not necessary for the analysis of asbestos. Recognition of appropriate colors along with the
proper morphology are deemed sufficient to
identify the commercial asbestos minerals.
Other techniques including SEM, TEM, and
XRD may be required to provide additional
information in order to identify other types
of asbestos.
Make a preparation in the suspected
matching high dispersion oil, e.g., n=1.550 for
chrysotile. Perform the preliminary tests to
determine
whether
the
fibers
are
birefringent or not. Take note of the morphological character. Wavy fibers are indicative of chrysotile while long, straight, thin,
frayed fibers are indicative of amphibole asbestos. This can aid in the selection of the
appropriate matching oil. The microscope is
set up and the polarization direction is noted
as in Section 4.4. Align a fiber with the polarization direction. Note the color. This is
the color parallel to the polarizer. Then rotate the fiber rotating the stage 90° so that
the polarization direction is across the fiber.
This is the perpendicular position. Again
§ 1915.1001
note the color. Both colors must be consistent with standard asbestos minerals in
the correct direction for a positive identification of asbestos. If only one of the colors
is correct while the other is not, the identification is not positive. If the colors in both
directions are bluish-white, the analyst has
chosen a matching index oil which is higher
than the correct matching oil, e.g. the analyst has used n = 1.620 where chrysotile is
present. The next lower oil (Section 3.5.)
should be used to prepare another specimen.
If the color in both directions is yellowwhite to straw-yellow-white, this indicates
that the index of the oil is lower than the
index of the fiber, e.g. the preparation is in
n = 1.550 while anthophyllite is present. Select the next higher oil (Section 3.5.) and prepare another slide. Continue in this fashion
until a positive identification of all asbestos
species present has been made or all possible
asbestos species have been ruled out by negative results in this test. Certain plant fibers
can have similar dispersion colors as asbestos. Take care to note and evaluate the morphology of the fibers or remove the plant fibers in pre-preparation. Coating material on
the fibers such as carbonate or vinyl may destroy the dispersion color. Usually, there
will be some outcropping of fiber which will
show the colors sufficient for identification.
When this is not the case, treat the sample
as described in Section 3.3. and then perform
dispersion staining. Some samples will yield
to Becke line analysis if they are coated or
electron microscopy can be used for identification.
5. References
5.1. Crane, D.T., Asbestos in Air, OSHA
method ID160, Revised November 1992.
5.2. Ford, W.E., Dana’s Textbook of Mineralogy; Fourth Ed.; John Wiley and Son,
New York, 1950, p. vii.
5.3. Selikoff,.I.J., Lee, D.H.K., Asbestos and
Disease, Academic Press, New York, 1978, pp.
3, 20.
5.4. Women Inspectors of Factories. Annual
Report for 1898, H.M. Statistical Office, London, p. 170 (1898).
5.5. Selikoff,.I.J., Lee, D.H.K., Asbestos and
Disease, Academic Press, New York, 1978, pp.
26, 30.
5.6. Campbell, W.J., et al, Selected Silicate
Minerals and Their Asbestiform Varieties,
United States Department of the Interior,
Bureau of Mines, Information Circular 8751,
1977.
5.7. Asbestos, Code of Federal Regulations,
29 CFR 1910.1001 and 29 CFR 1926.58.
5.8. National Emission Standards for Hazardous Air Pollutants; Asbestos NESHAP Revision, FEDERAL REGISTER, Vol. 55, No. 224, 20
November 1990, p. 48410.
5.9. Ross, M. The Asbestos Minerals: Definitions, Description, Modes of Formation, Physical and Chemical Properties and Health Risk to
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31
§ 1915.1001
29 CFR Ch. XVII (7–1–15 Edition)
the Mining Community, Nation Bureau of
Standards Special Publication, Washington,
D.C., 1977.
5.10. Lilis, R., Fibrous Zeolites and Endemic Mesothelioma in Cappadocia, Turkey,
J. Occ Medicine, 1981, 23, (8) ,548–550.
5.11. Occupational Exposure to Asbestos—
1972, U.S. Department of Health Education
and Welfare, Public Health Service, Center
for Disease Control, National Institute for
Occupational Safety and Health, HSM–72–
10267.
5.12. Campbell,W.J., et al, Relationship of
Mineral Habit to Size Characteristics for
Tremolite Fragments and Fibers, United States
Department of the Interior, Bureau of Mines,
Information Circular 8367, 1979.
5.13. Mefford, D., DCM Laboratory, Denver,
private communication, July 1987.
5.14. Deer, W.A., Howie, R.A., Zussman, J.,
Rock Forming Minerals, Longman, Thetford,
UK, 1974.
5.15. Kerr, P.F., Optical Mineralogy; Third
Ed. McGraw-Hill, New York, 1959.
5.16. Veblen, D.R. (Ed.), Amphiboles and
Other Hydrous Pyriboles—Mineralogy, Reviews
in Mineralogy, Vol 9A, Michigan, 1982, pp 1–
102.
5.17. Dixon, W.C., Applications of Optical Microscopy in the Analysis of Asbestos and
Quartz, ACS Symposium Series, No. 120, Analytical Techniques in Occupational Health
Chemistry, 1979.
5.18. Polarized Light Microscopy, McCrone
Research Institute, Chicago, 1976.
5.19. Asbestos Identification, McCrone Research Institute, G & G printers, Chicago,
1987.
5.20. McCrone, W.C., Calculation of Refractive Indices from Dispersion Staining Data,
The Microscope, No 37, Chicago, 1989.
5.21. Levadie, B. (Ed.), Asbestos and Other
Health Related Silicates, ASTM Technical
Publication 834, ASTM, Philadelphia 1982.
5.22. Steel, E. and Wylie, A., Riordan, P.H.
(Ed.), Mineralogical Characteristics of Asbestos, Geology of Asbestos Deposits, pp. 93–101,
SME-AIME, 1981.
5.23. Zussman, J., The Mineralogy of Asbestos, Asbestos: Properties, Applications and Hazards, pp. 45–67 Wiley, 1979.
APPENDIX L TO § 1915.1001—WORK PRACTICES
AND ENGINEERING CONTROLS FOR AUTOMOTIVE BRAKE AND CLUTCH INSPECTION, DISASSEMBLY, REPAIR AND ASSEMBLY—MANDA-
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TORY
This mandatory appendix specifies engineering controls and work practices that
must be implemented by the employer during automotive brake and clutch inspection,
disassembly, repair, and assembly operations. Proper use of these engineering controls and work practices by trained employees will reduce employees’ asbestos exposure
below the permissible exposure level during
clutch and brake inspection, disassembly, re-
pair, and assembly operations. The employer
shall institute engineering controls and
work practices using either the method set
forth in paragraph [A] or paragraph [B] of
this appendix, or any other method which
the employer can demonstrate to be equivalent in terms of reducing employee exposure
to asbestos as defined and which meets the
requirements described in paragraph [C] of
this appendix, for those facilities in which no
more than 5 pairs of brakes or 5 clutches are
inspected, disassembled, reassembled and/or
repaired per week, the method set forth in
paragraph [D] of this appendix may be used:
[A] Negative Pressure Enclosure/HEPA Vacuum
System Method
(1) The brake and clutch inspection, disassembly, repair, and assembly operations
shall be enclosed to cover and contain the
clutch or brake assembly and to prevent the
release of asbestos fibers into the worker’s
breathing zone.
(2) The enclosure shall be sealed tightly
and thoroughly inspected for leaks before
work begins on brake and clutch inspection,
disassembly, repair, and assembly.
(3) The enclosure shall be such that the
worker can clearly see the operation and
shall provide impermeable sleeves through
which the worker can handle the brake and
clutch inspection, disassembly, repair and
assembly. The integrity of the sleeves and
ports shall be examined before work begins.
(4) A HEPA-filtered vacuum shall be employed to maintain the enclosure under negative pressure throughout the operation.
Compressed-air may be used to remove asbestos fibers or particles from the enclosure.
(5) The HEPA vacuum shall be used first to
loosen the asbestos containing residue from
the brake and clutch parts and then to evacuate the loosened asbestos containing material from the enclosure and capture the material in the vacuum filter.
(6) The vacuum’s filter, when full, shall be
first wetted with a fine mist of water, then
removed and placed immediately in an impermeable container, labeled according to
paragraph (k)(8) of this section and disposed
of according to paragraph (l) of this section.
(7) Any spills or releases of asbestos containing waste material from inside of the enclosure or vacuum hose or vacuum filter
shall be immediately cleaned up and disposed of according to paragraph (l) of the
section.
[B] Low Pressure/Wet Cleaning Method
(1) A catch basin shall be placed under the
brake assembly, positioned to avoid splashes
and spills.
(2) The reservoir shall contain water containing an organic solvent or wetting agent.
The flow of liquid shall be controlled such
that the brake assembly is gently flooded to
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Occupational Safety and Health Admin., Labor
prevent the asbestos-containing brake dust
from becoming airborne.
(3) The aqueous solution shall be allowed
to flow between the brake drum and brake
support before the drum is removed.
(4) After removing the brake drum, the
wheel hub and back of the brake assembly
shall be thoroughly wetted to suppress dust.
(5) The brake support plate, brake shoes
and brake components used to attach the
brake shoes shall be thoroughly washed before removing the old shoes.
(6) In systems using filters, the filters,
when full, shall be first wetted with a fine
mist of water, then removed and placed immediately in an impermeable container, labeled according to paragraph (k)(8) of this
section and disposed of according to paragraph (l) of this section.
(7) Any spills of asbestos-containing aqueous solution or any asbestos-containing
waste material shall be cleaned up immediately and disposed of according to paragraph (l) of this section.
(8) The use of dry brushing during low pressure/wet cleaning operations is prohibited.
[C] Equivalent Methods
An equivalent method is one which has sufficient written detail so that it can be reproduced and has been demonstrated that the
exposures resulting from the equivalent
method are equal to or less than the exposures which would result from the use of the
method described in paragraph [A] of this appendix. For purposes of making this comparison, the employer shall assume that exposures resulting from the use of the method
described in paragraph [A] of this appendix
shall not exceed 0.016 f/cc, as measured by
the OSHA reference method and as averaged
over at least 18 personal samples.
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[D] Wet Method
(1) A spray bottle, hose nozzle, or other implement capable of delivering a fine mist of
water or amended water or other delivery
system capable of delivering water at low
pressure, shall be used to first thoroughly
wet the brake and clutch parts. Brake and
clutch components shall then be wiped clean
with a cloth.
(2) The cloth shall be placed in an impermeable container, labelled according to paragraph (k)(8) of this section and then disposed
of according to paragraph (l) of this section,
or the cloth shall be laundered in a way to
prevent the release of asbestos fibers in excess of 0.1 fiber per cubic centimeter of air.
(3) Any spills of solvent or any asbestos
containing waste material shall be cleaned
up immediately according to paragraph (l) of
this section.
§ 1915.1008
(4) The use of dry brushing during the wet
method operations is prohibited.
[59 FR 41080, Aug. 10, 1994, as amended at 60
FR 33344, June 28, 1995; 60 FR 33987–33995,
June 29, 1995; 60 FR 36044, July 13, 1995; 60 FR
50412, Sept. 29, 1995; 61 FR 43457, Aug. 23, 1996;
63 FR 35137, June 29, 1998; 67 FR 44545, 44546,
July 3, 2002; 70 FR 1143, Jan. 5, 2005; 71 FR
16674, Apr. 3, 2006; 71 FR 50191, Aug. 24, 2006;
73 FR 75587, Dec. 12, 2009; 76 FR 33610, June 8,
2011; 77 FR 17888, Mar. 26, 2012; 78 FR 9315,
Feb. 8, 2013]
§ 1915.1002 Coal tar pitch volatiles; interpretation of term.
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1002 of
this chapter.
[61 FR 31430, June 20, 1996]
§ 1915.1003 13
carcinogens
Nitrobiphenyl, etc.).
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1003 of
this chapter.
[61 FR 31430, June 20, 1996]
§ 1915.1004
alpha-Naphthylamine.
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1003 of
this chapter.
[61 FR 31430, June 20, 1996]
§ 1915.1005
[Reserved]
§ 1915.1006
Methyl chloromethyl ether.
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1003 of
this chapter.
[61 FR 31430, June 20, 1996]
§ 1915.1007 3,3′-Dichlorobenzidiene
(and its salts).
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1003 of
this chapter.
[61 FR 31430, June 20, 1996]
§ 1915.1008
bis-Chloromethyl ether.
NOTE: The requirements applicable to shipyard employment under this section are
identical to those set forth at § 1910.1003 of
this chapter.
[61 FR 31430, June 20, 1996]
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| File Type | application/pdf |
| File Modified | 2015-08-18 |
| File Created | 2015-08-18 |