BLS Handbook of Methods - Occupational Safety and Health Statistics

Chapter 9.
Occupational Safety and Health Statistics

ata on safety and health conditions for workers on
the job have been produced by the Bureau of Labor
Statistics (BLS) since before World War I. The first
safety and health report issued by BLS summarized industrial
accidents in the iron and steel industries during the war
period, presenting information on the frequency and severity
of injuries, the occupation of the injured workers, and the
nature of their injuries.1 Work-related illnesses also were the
subject of BLS studies conducted in the early 1900s, such as
the pioneering research on lead poisoning in the workplace
done by Dr. Alice Hamilton.2
It was not until the passage of the Occupational Safety
and Health Act of 1970 that Congress delegated to BLS
the responsibility for developing a comprehensive statistical
system covering work-related injuries, illnesses, and
fatalities in private industry. In 1972, BLS, in cooperation
with many state governments, designed the annual Survey
of Occupational Injuries and Illnesses (SOII) to estimate the
number and frequency of work-related injuries and illnesses
by detailed industry for the nation and for states participating
in the SOII. This survey information continues to be of value
to the safety and health community when deciding how to
allocate prevention resources among several hundred diverse
industries, across which, workers’ risks of injury and illness
vary widely.
As originally designed, however, the SOII had its
shortcomings. Although the survey identified industries
with dangerous work settings, it shed little light on the
circumstances of an injury or illness; for example, the survey
did not ask about the manner in which an incident occurred
and which occupations were involved.3 The SOII also failed
to produce a reliable count of workplace fatalities or profiles

D

1
The Safety Movement in the Iron and Steel Industry, Bulletin 234 (Bureau
of Labor Statistics, 1918).
2
The White-Lead Industry in the United States, Bulletin 95 (Bureau of
Labor, 1911).
3
Between the mid-1970s and early 1990s, a limited amount of data on case
circumstances of work-related injuries and illnesses and characteristics of
the workers involved were aggregated for selected states participating in the
Supplementary Data System and Work Injury Reports. For a description of
those programs, see BLS Handbook of Methods, Bulletin 2414 (Bureau of
Labor Statistics, 1992), chapter 14.

IN THIS CHAPTER
Part I. Common Coding Systems

North American Industry Classification System (NAICS)......... 2

Standard Occupational Classification (SOC).............................. 3

Occupational Injury Illness Classification System (OIICS)....... 4

Race and Ethnicity Standards..................................................... 4
Part II. Survey of Occupational Injuries and Illnesses........................ 5
Background................................................................................. 5

SOII Definitions.......................................................................... 6

SOII Measures............................................................................ 8

Scope of the SOII........................................................................ 9

State Participation in the SOII.................................................... 9

SOII Sample Design................................................................. 10

SOII Data Collection................................................................. 10

SOII Estimation Procedures...................................................... 11

Uses and Limitations of SOII Estimates................................... 15

Survey Forms............................................................................ 15
Part III. Census of Fatal Occupational Injuries................................. 15
Background............................................................................... 16

CFOI Definitions....................................................................... 16

CFOI Collection Methods......................................................... 17

CFOI Measures......................................................................... 17

Fatal Injury Rates...................................................................... 17

Presentation of CFOI Data........................................................ 19

Uses and Limitations of CFOI Data.......................................... 20
Part IV. Special Topic Surveys.......................................................... 21
Technical References........................................................................ 22

depicting the victims’ demographics and the circumstances
surrounding their deaths.
In 1987, a National Academy of Sciences study recommended that these deficiencies be corrected by collecting
detailed data on severe, nonfatal occupational injuries and
illnesses reported in the SOII and by compiling complete
accounts of occupational fatalities from administrative records, such as death certificates and workers’ compensation
reports.4 This critical review of the SOII, which highlighted
4
See E.S. Pollack and D.F. Keimig, eds., Counting Injuries and Illnesses
in the Workplace: Proposals for a Better System (Washington, National
Research Council, National Academy Press, 1987), pp. 103–06.

North American Industry Classification
System (NAICS)

longstanding deficiencies, provided the impetus for its redesign.
With congressional funding, technical support from the
safety and health community, and assistance from some 40
participating states, BLS began a multiyear effort to redesign
and test an improved safety and health statistical system,
which was fully implemented in 1992. Beginning that year,
SOII estimates of nonfatal workplace injuries and illnesses
were expanded to profile detailed case circumstances and
worker characteristics for cases that involved days away
from work, and a separate Census of Fatal Occupational
Injuries (CFOI) was established to capture counts and profiles
of work-related fatalities. (For more information on case
circumstances and worker characteristics, see discussion of
the Occupational Injury and Illness Classification system
and the Standard Occupational Classification system in
Part I. Common Coding Systems, which follows this section.)
The changes to the BLS Occupational Safety and Health
Statistics (OSHS) program implemented in 1992 added
two new outputs for the program. The three distinct outputs
include the Census of Fatal Occupational Injuries (CFOI);
Survey of Occupational Injuries and Illnesses—Case and
Demographics (SOII—C&D); and the original Survey of
Occupational Injuries and Illnesses—Annual Summary
(SOII—AS). The results of the survey and census are
reported in separate news releases published annually by the
following titles:
•

Census of Fatal Occupational Injuries includes
detailed case circumstances and worker
characteristics for work-related fatalities (CFOI)

•

Workplace Injuries and Illnesses includes industrylevel estimates of nonfatal work-related injuries and
illnesses from the SOII (SOII—AS)

•

Nonfatal Occupational Injuries and Illnesses
Requiring Days Away From Work includes detailed
case circumstances and worker characteristics for
cases involving days away from work from the SOII
(SOII—C&D)

The SOII and CFOI adopted a new industry classification
system beginning with data for reference year 2003. The
Standard Industrial Classification (SIC) system served as the
foundation for SOII and CFOI statistics since the inception
of each program—1972 and 1992, respectively, and was
revised numerous times during its life cycle (most recently in
1987) to account for changes in the composition of the U.S.
economy.
Despite periodic updates to the SIC system, increasing
criticism led to the development of a new, more comprehensive
system that reflects more recent and rapid economic changes.
Many industrial changes were not accounted for under the
SIC system, such as recent developments in information
services, new forms of health care provision, expansion of
the services sector, and high-tech manufacturing.
The North American Industry Classification System
(NAICS) was developed in cooperation with Canada and
Mexico to replace the SIC system, and it was one of the
most profound changes for statistical programs focused
on measuring economic activities. NAICS uses a processoriented conceptual framework to group establishments into
industries according to the activity in which they are primarily
engaged. Establishments using similar raw material inputs,
similar capital equipment, and similar labor are classified
in the same industry. In other words, establishments that do
similar things in similar ways are classified together.
NAICS provides a new tool to ensure that SOII and CFOI
statistics accurately reflect changes in a dynamic U.S. economy. The downside of this change is that these improved
statistics resulted in time series breaks due to the significant
differences between SIC and NAICS. Every sector of the
economy was restructured and redefined under NAICS. A
new Information sector combined communications, publishing, motion picture and sound recording, and online services,
recognizing our information-based economy. NAICS restructured the Manufacturing sector to recognize new high-tech
industries. A new subsector was devoted to computers and
electronics, including reproduction of software. Retail trade
was redefined. In addition, eating and drinking places were
transferred to a new Accommodation and Food Services sector. The difference between the Retail Trade and Wholesale
Trade sectors is now based on how each store conducts business. For example, many computer stores were reclassified
from wholesale to retail. Nine new service sectors and 250
new service-providing industries were recognized with the
adoption of the NAICS revision in 2002.
NAICS uses a 6-digit hierarchical coding system to classify
economic activities into 20 industry sectors—4 sectors are
mainly goods-producing sectors and 16 are entirely serviceproviding sectors. This 6-digit hierarchical structure allows
greater coding flexibility than the 4-digit structure of the
SIC. NAICS allows for the identification of 1,170 industries
compared with the 1,004 found in the SIC system.

Several changes that have had significant impacts on data
from the BLS safety and health statistics program, including
updated recordkeeping requirements, new industry and
occupation classification systems, and changes in race and
ethnicity standards, are discussed in Part I. Common Coding
Systems.

Part I. Common Coding Systems
The Survey of Occupational Injuries and Illnesses (SOII)
and the Census of Fatal Occupational Injuries (CFOI) share
several systems to classify industry, occupation, and case
circumstances and worker characteristics. Changes among
these systems over the past several years have significantly
impacted SOII and CFOI outputs, as described below.

2

In late 2004, BLS began publishing survey year 2003
occupational safety and health statistics using NAICS, first
with the CFOI in September, followed by summary estimates
from the SOII in December. In March 2005, BLS published
NAICS-based detailed case circumstances and worker
characteristics estimates from the 2003 SOII. Because of the
substantial differences between the NAICS and SIC systems,
the results by industry since 2003 constitute a break in series,
and users are advised against making comparisons between
the 2003 industry categories and the results for previous
years.
The NAICS 2002 structure was revised on a planned
5-year cycle to reflect changes in the economy, resulting
in the NAICS 2007 standard. SOII and CFOI industry data
incorporated NAICS 2007 coding with the release of data for
2009. The differences between the NAICS 2002 and NAICS
2007 were not as broad as those between SIC and NAICS.
Therefore, adoption of NAICS 2007 did not result in series
breaks. For additional information regarding differences
between NAICS 2002 and NAICS 2007, visit the U.S.
Census Bureau NAICS webpage at http://www.census.gov/
eos/www/naics/.

• Natural resources and mining—combining Agriculture,
forestry, fishing, and hunting (NAICS 11), and Mining
(NAICS 21)
• Trade, transportation, and utilities—combining
Wholesale (NAICS 42) and Retail trade (NAICS 44–
45), Transportation and warehousing (NAICS 48–49),
and Utilities (NAICS 22)
• Financial activities—combining Finance and insurance
(NAICS 52) and Real estate and rental and leasing
(NAICS 53)
• Professional and business services—combining
Professional, scientific, and technical services (NAICS
54); Management of companies and enterprises
(NAICS 55); and Administrative and support and waste
management and remediation services (NAICS 56)
• Education and health services—combining Education
services (NAICS 61) and Health care and social
assistance (NAICS 62)
• Leisure and hospitality—combining Arts, entertainment,
and recreation (NAICS 71) and Accommodation and
food services (NAICS 72)

The following list identifies the individual goods-producing
and service-providing sectors according to 2007 NAICS
classifications:

Standard Occupational Classification
(SOC)

Beginning with the 2011 reference year, the CFOI and
the SOII began using the 2010 Standard Occupational
Classification system for coding occupations. Prior to 2011,
the 2000 Standard Occupational Classification system for
occupations was used. Because of the differences between
the current and older 2000 SOC version, CFOI and SOII
results by occupation in 2011 constitute a break in series, and
users are advised against making comparisons between the
2011 (and subsequent years) occupation categories and the
results for previous years. The 2010 SOC system classifies
workers at four levels of aggregation:

• Goods-producing NAICS sectors:
• Agriculture, forestry, fishing, and hunting (NAICS 11)
• Mining (NAICS 21)
• Construction (NAICS 23)
• Manufacturing (NAICS 31–33)
• Service-providing NAICS sectors:
• Wholesale trade (NAICS 42)
• Retail trade (NAICS 44–45)
• Transportation and warehousing (NAICS 48–49)
• Utilities (NAICS 22)
• Information (NAICS 51)
• Finance and insurance (NAICS 52)
• Real estate and rental and leasing (NAICS 53)
• Professional, scientific, and technical services (NAICS
54)
• Management of companies and enterprises (NAICS
55)
• Administrative and support and waste management
and remediation services (NAICS 56)
• Education services (NAICS 61)
• Health care and social assistance (NAICS 62)
• Arts, entertainment, and recreation (NAICS 71)
• Accommodation and food services (NAICS 72)
• Other services (except Public administration) (NAICS
81)
• Public administration (NAICS 92)

• Major group
• Minor group
• Broad occupation
• Detailed occupation
All occupations are clustered into one of 23 major groups,
within which are 97 minor groups, 461 broad occupations,
and 840 detailed occupations. Occupations with similar
skills or work activities are grouped at each of the four levels
of hierarchy to facilitate comparisons. For example, Life,
Physical, and Social Science Occupations (19-0000) is divided
into four minor groups: Life Scientists (19-1000), Physical
Scientists (19-2000), Social Scientists and Related Workers
(19-3000), and Life, Physical, and Social Science Technicians
(19-4000). Life Scientists contains broad occupations such as
Agriculture and Food Scientists (19-1010), and Biological
Scientists (19-1020). The broad occupation Biological
Scientists includes detailed occupations such as Biochemists
and Biophysicists (19-1021) and Microbiologists (19-1022).

In addition to these NAICS sectors, SOII and CFOI statistics
are tabulated for several additional NAICS aggregations
that are unique to BLS, including the following:

3

The OIICS revision in September 2010 was the first major revision since the 1992 manual. The BLS OIICS Revision Team developed the new manual using input from many
stakeholders. In February 2008, BLS issued a Federal Register Notice requesting suggestions for proposed changes to the
manual. In addition, the OSHS program sent out numerous
letters and e-mails to others who use the OIICS to classify
injury and illness data. In April 2010, the OSHS program sent
a draft of the revised OIICS manual to interested parties for
their comments. The team considered comments received,
made revisions, and completed the final manual in September
2010. OIICS 2.0 differs significantly enough from the original version to be considered a break in series, so data may not
be comparable to previous years.
The SOII—C&D and CFOI use five classifications to
describe each incident that led to a serious nonfatal injury or
illness or a fatal injury:

Each item in the hierarchy is designated by a six-digit
code. The first two digits of the SOC code represent the
major group; the third digit represents the minor group; the
fourth and fifth digits represent the broad occupation; and the
detailed occupation is represented by the sixth digit. Major
group codes end with 0000 (e.g., 33-0000, Protective Service
Occupations), minor groups end with 000 (e.g., 33-2000, Fire
Fighting Workers), and broad occupations end with 0 (e.g.,
33-2020, Fire Inspectors). (The zeros are not always printed.)
All residuals (“Other,” “Miscellaneous,” or “All Other”),
whether at the detailed or broad occupation or minor group
level, contain a 9 at the level of the residual. Detailed residual
occupations end in 9 (e.g., 33-9199, Protective Service
Workers, All Other), broad occupations which are minor
group residuals end in 90 (e.g., 33-9190, Miscellaneous
Protective Service Workers), and minor groups which are
major group residuals end in 9000 (e.g., 33-9000, Other
Protective Service Workers):

• Nature—the physical characteristics of the disabling
injury or illness, such as cuts and lacerations, fractures,
sprains and strains, or electrocution

• 33-0000 Protective Service Occupations
•

33-9000 Other Protective Service Workers
•

• Part of body affected—the part of body directly linked to
the nature of injury or illness cited, such as finger, arm,
back, or body systems

33-9190 Miscellaneous Protective Service
Workers
• 33-9199 Protective Service Workers, All
Other

• Event or exposure—the manner in which the injury
or illness was produced or inflicted, such as caught in
running equipment; slips, trips, or falls; overexertion; or
contact with electric current

Also note, prior to 2003, both CFOI and SOII used the
U.S. Census Bureau Occupational Coding structure to code
occupation. Beginning with 2003 data, CFOI and SOII-C&D
both used 2000 SOC for the first time to classify occupation.
Because of the substantial differences in the Census Bureau
Occupational Coding structure and the 2000 SOC system,
users are advised against making comparisons between the
2003–2010 occupation categories and the results for years
before 2003.

• Source—the object, substance, exposure, or bodily
motion that was responsible for producing or inflicting
the disabling condition, such as machinery, ground,
patient, or electrical wiring
• Secondary source—the object, substance, or person, if
any, that generated the source of injury or illness or that
contributed to the event or exposure, such as ice or water
that contributed to a fall

Occupational Injury and Illness
Classification System (OIICS)

Figure 1 is an illustrative example of how SOII—C&D may
use OIICS codes to describe an injury incident.(see page 5)

The Occupational Injury and Illness Classification System
(OIICS) was developed by BLS to provide a consistent set
of classifications of the circumstances of the characteristics
associated with workplace injuries, illnesses, and fatalities.
The circumstances of each case are classified based on the BLS
OIICS manual. The Bureau of Labor Statistics Classification
Structure Team developed the original OIICS with input from
data users and states participating in the BLS Occupational
Safety and Health Statistics (OSHS) federal/state cooperative
programs. The original system was released in December
1992 and approved for use as the American National Standard
for Information Management for Occupational Safety and
Health in 1995 (ANSI Z16.2—1995). In September 2007,
OSHS staff updated the 1992 manual to incorporate various
interpretations and corrections.

Race and Ethnicity Standards
Both the Census of Fatal Occupational Injuries (CFOI)
and the Survey of Occupational Injuries and Illnesses
(SOII—C&D) were implemented in 1992, following
recommendations of a National Academies of Science review
highlighting the need to capture detailed case circumstances
and worker characteristics for fatal and nonfatal workplace
incidents, respectively. At their inception, each of these series
used separate methods to categorize the race or ethnicity
of injured or ill workers. The SOII—C&D categorized
Hispanics separately, while the CFOI categorized Hispanics
by race (e.g., Black or White) and also provided a total count

4

Figure 1

and ethnicity is one of the few data elements that are optional
in the SOII. This resulted in 37 percent of the cases involving
days away from work for which race and ethnicity were not
reported in the 2009 SOII.

of Hispanics. The remaining race and ethnicity categories for
both series were
•
•
•
•

White
Black
Asian or Pacific Islander
American Indian or Native Alaskan.

Part II. Survey of Occupational
Injuries and Illnesses

The classification of workers by race and ethnicity for the
CFOI and the SOII is based on the 1997 Standards for
Federal Data on Race and Ethnicity as defined by the Office
of Management and Budget. In 1999, the CFOI amended race
categories so that Hispanics no longer counted as a race, but
solely as an ethnicity. Three additional changes were also
incorporated to race and ethnicity categories:

Background
The current BLS Survey of Occupational Injuries and Illnesses
(SOII) evolved from annual BLS surveys first conducted in
the 1940s, when injury recordkeeping standards became
sufficiently uniform to permit the collection of nationwide
work injury data. Spanning 3 decades, those nationwide
surveys proved useful in measuring and monitoring injury
frequency and severity, but they had two major limitations.
First, the survey data were compiled from and represented
only employers who volunteered to record and report work
injuries. Second, work injuries were limited to those that
resulted in death, permanent impairment, or temporary
disability, defined as unable to perform regular job duties
beyond the day of injury. Thus, survey estimates excluded
many employers and, by definition, numerous cases that

• Asian became a separate category.
• Native Hawaiian was combined with Pacific
Islander to form a new category, Native Hawaiian
or Pacific Islander.
• “Multirace” was added.
In 2002, the SOII—C&D incorporated these same race
categories. One result of this revision is that individuals may
be categorized in more than one race or ethnic group. Race

5

1, 2002, and used by employers to keep logs and case details
of such incidents throughout the survey (calendar) year. (See
the Technical References section for citations of instructional
materials useful in understanding the types of cases recorded
under current recordkeeping guidelines.)

required medical treatment (beyond first aid) or restricted
work duties but did not result in days away from work.
These and other limitations were addressed in a landmark
piece of safety legislation passed by the Congress: the
Occupational Safety and Health Act of 1970. The 1970 act
and its implementing regulations required that most private
industry employers regularly maintain records (logs) and
prepare reports on work-related injuries and illnesses, which
include all disabling, serious, or significant injuries and
illnesses, whether or not involving time away from work.5
The 1970 act called for a wider statistical net to gather work
injury and illness data and to measure their numbers and
incidence rates. The current mandatory survey, modified on
several occasions to incorporate various changes discussed in
later sections, still meets the basic requirements of the 1970
act for counts and rates covering a broad spectrum of work
injuries and illnesses in various work settings. Beginning
with the 1992 calendar year, the SOII began to collect
information on the circumstances of the most serious of its
nonfatal cases—those involving days away from work—and
the characteristics of workers sustaining such injuries and
illnesses.
The SOII estimates the number and frequency (incidence
rates) of workplace injuries and illnesses based on logs kept
by employers during the year. These records reflect not
only the year’s injury and illness experience, but also the
employer’s understanding of which cases are work-related
under recordkeeping guidelines promulgated by the U.S.
Department of Labor’s Occupational Safety and Health
Administration (OSHA). Effective January 1, 2002, OSHA
revised its requirements for recording occupational injuries
and illnesses. These requirements were further refined to
include guidelines for recording of hearing loss cases as
a separate category of illness, for which SOII estimates
are available beginning with the 2004 survey year. Details
about the revised requirements, including a summary of
the revisions and a comparison between the old and new
requirements, are available online at http://www.osha.gov/
recordkeeping/index.html or from OSHA’s Office of Public
Affairs, available via telephone at 202-693-1999.
Because of the revised recordkeeping requirements, SOII
estimates for 2002 are not comparable with those from
prior years. Similarly, SOII estimates since 2003 are not
comparable to those for previous years owing to changes in
industry and occupation coding systems. (See Part I. Common
Coding Systems for discussion of NAICS and SOC.) The
SOII was not designed to be able to determine the impact
of these revisions on the estimates of nonfatal occupational
injuries and illnesses. (The revised recordkeeping definitions
are reflected in the SOII Definitions section.)

Recording criteria
Nonfatal recordable workplace injuries and illnesses are
those that result in any one or more of the following:
•
•
•
•

Loss of consciousness
Days away from work
Restricted work activity or job transfer
Medical treatment beyond first aid

In addition to these four criteria, employers must also
record any significant work-related injuries or illnesses that
are diagnosed by a physician or other licensed health care
professional or other instances that meet additional criteria
discussed below. Significant work-related injuries or illnesses
include cancers, chronic irreversible diseases, fractured or
cracked bones (including teeth), or punctured eardrums.
Additional cases that must be recorded as workplace injuries
or illnesses include the following:
•

Any needlestick injury or cut from a sharp object
that is contaminated with another person’s blood or
other potentially infectious material

•

Any case requiring an employee to be medically
removed under the requirements of an OSHA health
standard

•

Tuberculosis infection as evidenced by a positive
skin test or diagnosis by a physician or other licensed
health care professional after exposure to a known
case of active tuberculosis

An employee’s hearing test (audiogram) reveals
1) that the employee has experienced a Standard
Threshold Shift (STS) in hearing in one or both
ears (averaged at 2kHz, 3kHz, and 4kHz) and 2) the
employee’s total hearing level is 25 decibels (dB)
or more above audiometric zero (also averaged at
2kHz, 3kHz, and 4kHz) in the same ear(s) as the
STS.
Additional details regarding recordability of nonfatal workrelated injuries and illnesses can be found in the OSHA
Recordkeeping Handbook.
•

Injuries and illnesses
The distinction between occupational injury and occupational
illness was eliminated from OSHA recordkeeping guidelines
when revisions were implemented in 2002. The OSHA
guidelines now define an injury or illness as an abnormal
condition or disorder. For purposes of clarification for the
SOII, these terms are defined separately below. Nature codes
from the OIICS manual are used to code distinct injuries and

SOII Definitions

The following definitions of nonfatal occupational injuries
and illnesses used in the SOII are the same as those established
in the recordkeeping guidelines of OSHA, effective January
5
See section 24(a) of the Occupational Safety and Health Act of 1970
(Public Law 91–596).

6

illnesses for more severe cases. (See discussion of OIICS in
Part I. Common Coding Systems.)
•

Occupational injury is any injury, such as a cut,
fracture, sprain, amputation, and so forth, that
results from a work-related event or from a single
instantaneous exposure in the work environment.

•

Occupational illness is any abnormal condition or
disorder caused by exposure to factors associated
with employment, other than those resulting from
an instantaneous event or exposure. It includes
acute and chronic illnesses or diseases that may be
caused by inhalation, absorption, ingestion, or direct
contact. Five categories of occupational illnesses and
disorders are used to classify recordable illnesses,
described as follows. Examples of each category
are provided, but these are not a complete listing of
the types of illnesses and disorders that are counted
under each category. (See the OIICS manual for a
more comprehensive list of injuries and illnesses
and their associated codes.)
• Occupational skin diseases or disorders are
illnesses involving the worker’s skin that are
caused by work exposure to chemicals, plants, or
other substances. Examples: Contact dermatitis,
eczema, or rash caused by primary irritants and
sensitizers or poisonous plants; oil acne; friction
blisters; chrome ulcers; or inflammation of the
skin.
•

•

•

Hearing loss. Noise-induced hearing loss is
defined for recordkeeping purposes as a change
in hearing threshold relative to a baseline
audiogram of an average of 10 dB or more in
either ear at 2kHz, 3kHz, and 4kHz, and the
employee’s total hearing level is 25 dB or more
above audiometric zero (also averaged at 2kHz,
3kHz, and 4kHz) in the same ear(s).

•

All other occupational illnesses. Includes all
other occupational illnesses not covered in the
preceding categories. Examples: Heatstroke,
sunstroke, heat exhaustion, heat stress, and
other effects of environmental heat; freezing,
frostbite, and other effects of exposure to low
temperatures; decompression sickness; effects
of ionizing radiation (isotopes, x rays, radium);
effects of nonionizing radiation (welding flash,
ultraviolet rays, lasers); anthrax; bloodborne
pathogenic diseases, such as AIDS, HIV, hepatitis
B, or hepatitis C; brucellosis; malignant or benign
tumors; histoplasmosis; coccidioidomycosis;
conditions due to repeated motion, vibration,
or pressure, such as carpal tunnel syndrome;
synovitis, tenosynovitis, and bursitis; and
Raynaud’s phenomena.

Case types
Nonfatal injury and illness estimates are tabulated from SOII
data for several types of cases, including the following:
• Days-away-from-work, job transfer, or restriction
(DART) cases are those which involve days away
from work (beyond the day of injury or onset of
illness), or days of job transfer or restricted work
activity, or both.

Respiratory conditions are illnesses associated
with breathing hazardous biological agents,
chemicals, dusts, gases, vapors, or fumes in
the workplace. Examples: Silicosis; asbestosis;
pneumonitis; pharyngitis; rhinitis or acute
congestion; farmer’s lung; beryllium disease;
tuberculosis; occupational asthma; reactive
airways dysfunction syndrome (RADS);
chronic
obstructive
pulmonary
disease
(COPD); hypersensitivity pneumonitis; toxic
inhalation injury, such as metal fume fever;
chronic obstructive bronchitis; and other
pneumoconioses.

• Days-away-from-work cases are those which
result in days away from work (beyond the day
of injury or onset of illness). The number of days
away from work for these cases is determined
according to the number of calendar days (not
workdays) that an employee was unable to work,
even if the employee was not scheduled to work
those days. The day on which the employee was
injured or became ill is not counted. These cases
may also include days of job transfer or restricted
work activity in addition to days away from
work. Take the case of an employee who suffers a
work-related injury resulting in 5 days away from
work. Upon returning to work, the employee
was unable to perform normal duties associated
with the job for an additional 3 days (i.e., the
employee was on restricted work activity). This
case would be recorded as a days-away-fromwork case with 5 days away from work and 3
days of restricted work activity. The number of

Poisoning includes disorders evidenced by
abnormal concentrations of toxic substances
in blood, other tissues, other bodily fluids,
or the breath that are caused by the ingestion
or absorption of toxic substances into the
body. Examples: Poisoning by lead, mercury,
cadmium, arsenic, or other metals; poisoning
by carbon monoxide, hydrogen sulfide, or other
gases; poisoning by benzol, carbon tetrachloride,
or other organic solvents; poisoning by
insecticide sprays, such as parathion or lead
arsenate; poisoning by other chemicals, such as
formaldehyde.

7

days away for which employers are required to
report is “capped” at 180 calendar days.

• Source and secondary source of injury or illness,
• Event or exposure.
Other circumstances include
• Day of the week the incident occurred,
• Time of day the incident occurred,
• Hours of work before the incident occurred.

• Job transfer or restriction cases are those which
result only in job transfer or restricted work
activity. This occurs when, as the result of a
work-related injury or illness, an employer keeps
or health care professional recommends keeping
an employee from doing the routine functions of
his or her job or from working the full workday
that the employee would have been scheduled to
work before the injury or illness occurred. This
may include the following instances:

See Part I. Common Coding Systems for additional details
on OIICS.
Worker characteristics
In addition to the aforementioned case circumstances, several
worker characteristics are collected and published in the SOII
for injuries and illnesses involving days away from work.
Worker characteristics are coded from information supplied
by the employer, supplemented by employer descriptions
(narratives) of how the incident occurred include the
following:
• Occupation (See Part I. Common Coding Systems
for discussion of SOC.)

• An employee is assigned to another job on a
temporary basis
• An employee works at a permanent job less
than full time
• An employee works at a permanently assigned
job but is unable to perform all duties normally
connected with it.

• Industry (See Part I. Common Coding Systems for
discussion of NAICS.)

The day on which the injury or illness occurred is not counted
as a day of job transfer or restriction. Workers who continue
working after incurring an injury or illness in their regularly
scheduled shift but produce fewer goods or services are not
considered to be in restricted activity status. They must be
restricted from performing their routine work functions to be
counted in this category.
•

• Age and age groups
• Race or ethnic origin (See Part I. Common Coding
Systems for discussion race and ethnicity.)
• Gender

Other recordable cases are those which are recordable
injuries or illnesses under OSHA recordkeeping
guidelines, but which do not result in any days
away from work, nor a job transfer or restriction,
beyond the day of the injury or onset of illness. For
example, John cut his finger on machinery during
his Wednesday afternoon workshift. The injury
required medical attention, for which John received
sutures at the local emergency room. John was able
to return to his normally scheduled workday on the
following day (Thursday) and performed his typical
work duties without any restrictions.

• Length of service

SOII Measures

The number and incidence rate of nonfatal workplace injuries
and illnesses are reported nationwide by industry (NAICS)
for the following types of cases:
• Total recordable cases
• Days-away-from-work, job transfer, or restriction cases
• Days-away-from-work cases
• Days of job transfer or restriction cases
• Other recordable cases

Case circumstances
Information about the circumstances of nonfatal occupational
injuries and illnesses cases involving days away from
work are collected from employers OSHA case forms and
classified using definitions and rules of selection stipulated
in the BLS Occupational Injury and Illness Classification
System (OIICS) manual, cited among technical references
at the end of this chapter. The following case circumstances
are used in the SOII to describe these injuries and illnesses
from different perspectives.

See the SOII Definitions section for additional details.
Days-away-from-work cases, which may also involve job
transfer or restricted workdays, are a subset of days away
from work, job transfer, or restriction (DART) cases. For
cases involving days away from work, the SOII presents
the case circumstances and worker characteristics by the
following:
• Case counts
• Incidence rates

• Nature of injury or illness,
• Part of body affected,

• Percent distributions

8

involving days away from work, job transfer, or restriction,
or other recordable cases. Incidence rates are available for
injuries and illnesses combined by the aforementioned case
types and for total recordable cases of injuries only. For
illnesses, incidence rates are available for total illness cases
and separately for the five illness categories defined in the
SOII Definitions section. Incidence rates for injury and illness
cases involving days away from work are also available for
specific case circumstances. For example, the incidence rates
associated with carpal tunnel syndrome, back injury cases,
injuries inflicted by health care patients, or disabling falls to
a lower level.
Beginning with survey year 2006, incidence rates are
also available for selected worker characteristics, including
age groups, gender, detailed occupation, and occupation
groups for national estimates and by age group, gender, and
occupation group for state estimates. (See section below on
State Participation in the SOII for description of availability
of state estimates.) These demographic rates for both national
and state estimates are available cross-tabulated by the
aforementioned circumstances—nature, part, source, and
event. Beginning with survey year 2009, incidence rates by
occupation in state government and local government are
also available.

The SOII also includes measures of severity for days-awayfrom-work cases:
• Median number of days away from work
• Number of days away from work by case count and
percent distribution
These severity measures are presented nationwide by
industry, by occupation, by the circumstances (nature, part,
source, and event), and for select worker characteristics
(including gender, age group, length of service, and race or
ethnic origin).
For cases involving days away from work, the median
number of workdays lost and a number and percent
distribution of days-away-from-work cases by their duration
(see below) are provided. The median number of days away
from work provides the middle observation of the number
of days missed associated with the particular characteristic
that is being measured (i.e., half of the cases involved
more days away from work and half of the cases involved
fewer days away from work than the median). The percent
distribution measures are presented nationwide, by industry,
and for the aforementioned case circumstances and worker
characteristics for cases involving the following:

Scope of the SOII

• 1 day away from work

The sample of workplaces selected by BLS for participation
in the SOII consists of approximately 230,000 private
industry establishments each year. SOII data are solicited
from employers having 11 employees or more in Agricultural
production, and from all employers in all other industries.
Starting with survey year 2008, SOII also collects data from
state and local government establishments to provide estimates
of occupational injuries and illnesses among government
workers for the nation and each participating state. Prior to
2008, state and local government injury and illness estimates
were available for only a selection of states and at varying
levels of detail. The SOII uses data from the Mine Safety and
Health Administration of the U.S. Department of Labor and
the Federal Railroad Administration of the U.S. Department
of Transportation.
Self-employed persons are not considered to be employees
under the 1970 act. Private households (NAICS 814), the
United States Postal Service (NAICS 491), and federal
government workers are out of scope for the SOII.

• 2 days away from work
• 3–5 days away from work
• 6–10 days away from work
• 11–20 days away from work
• 21–30 days away from work
• 31 or more days away from work
Incidence rates permit comparison among industries and
establishments of varying sizes. They express various
measures of injuries and illnesses in terms of a constant
reflecting exposure hours in the work environment—for
example, 200,000 employee hours or the equivalent of 100
full-time employees working for 1 year—thus allowing
for a common statistical base regardless of the number of
employees. In this way, a firm with 5 cases recorded for 70
employees can compare its injury and illness experience
to that of an entire industry with 12,000 cases for 150,000
employees. (The method of calculating incidence rates is
discussed in the SOII Estimation Procedures section.)
Incidence rates also are useful in evaluating the safety
performance of a particular industry over time or in
comparing state-to-state variations in an industry’s safety
record. Such comparisons are possible using the total
recordable case incidence rate or the incidence rate for cases

State Participation in the SOII
The SOII shares costs evenly with participating states to
develop estimates of occupational injuries and illnesses for
each participating state and the nation. BLS collects data in
nonparticipating states to support the national estimates only.
The participating state agencies collect and process the data
from which state and national estimates are tabulated using
standardized procedures and systems established by BLS to

9

a state wishes to produce an estimate. For example, a state
may select to target estimates for Hospitals (NAICS 622).
This TEI would include establishments in General medical
and surgical hospitals (NAICS 622110), Psychiatric and
substance abuse hospitals (NAICS 622210), and Specialty
hospitals, except psychiatric and substance abuse (NAICS
622310). A sampling cell is defined by state, ownership,
TEI, and size class for which an estimate will be tabulated.
Size classes are based on an establishment’s average annual
employment, as defined below:

insure uniformity and consistency among the states. BLS
designs and selects the survey sample for each state, though
states make decisions about the overall size of the sample.
To further ensure comparability and reliability of SOII
estimates, BLS provides training and continuing technical
assistance, reviews the establishment data, and validates the
survey results.
State participation in the SOII varies by year, depending on
funding decisions in each state. In 2009, nonfatal workplace
injuries and illnesses estimates for private industry were
tabulated separately for 44 participating states, cities, and
territories. Beginning with 2008, BLS published estimates of
injuries and illnesses to state and local government workers
for the nation as a whole and for each participating state.
Prior to 2008, about half of the participating states collected
and published estimates of injuries and illnesses to state and
local government workers. The level of industry detail for
which state estimates are tabulated varies and is based on
the needs determined by each state. Estimates for three U.S.
territories—Guam, Puerto Rico, and the Virgin Islands—are
not included in the tabulation of national estimates. Estimates
for the participating states, cities, and territories can be
accessed electronically at http://www.bls.gov/iif/oshstate.
htm.

• Size class 1 = establishments with 1–10 employees
• Size class 2 = establishments with 11–49 employees
• Size class 3 = establishments with 50–249 employees
• Size class 4 = establishments with 250–999 employees
• Size class 5 = establishments with 1,000 or more
employees
In the SOII, the variability of the incidence rate for total
recordable cases (TRC) of injuries and illnesses is used as
the primary variable for determining allocation of the sample,
since there is a high correlation between these cases and
other important characteristics of the data being estimated.
Historical state TRC rates are used to calculate the variance.
The optimal allocation procedure distributes the sample to
the industries in a manner intended to minimize the variance
of the total number of recordable cases in the universe or,
alternatively, the incidence rate of recordable cases in the
universe. In strata with higher variability of the data, a larger
sampling is selected.
For some sampling cells, it is necessary to select all
frame units in the cell in order to meet minimum sampling
requirements or to ensure that an adequate number of units
are sampled to produce accurate and reliable estimates for
the cell.
Once sampling is complete and all necessary reviews and
adjustments have been made, sampling weights are calculated
for units selected in each sampling cell. A maximum weight
threshold is applied to sample units. Sampling weights are
calculated by dividing the number of frame units in the
sampling cell by the number of sample units in that cell as
follows:

SOII Sample Design

A two-stage process is used to select a sample from which
estimates are generated for the SOII. The first stage involves the
selection from a frame including all in-scope establishments
that will be required to participate in the SOII (i.e., sample
units). The second stage is the selection of sample cases
involving days away from work from the establishments that
have been selected. All cases involving days away from work
are collected from most establishments. However, as a way to
reduce respondent burden, establishments that are predicted
to have a large number of cases involving days away from
work are instructed to provide a subsample of their cases by
reporting only those cases that occurred in specified months.
Because the SOII is a federal-state cooperative program
and the data are designed to meet the needs of the states,
an independent sample is selected for each participating
state, city, or territory. The sample is selected to represent
all in-scope private industries, state government, and local
government. The sample size for the SOII is dependent upon
the
• Number and kind of cases for which estimates are
needed,
• Industries for which estimates are desired,

where:

ƒ’Ž‡‡‹‰Š– ൌ 

ܰ௨
݊௦

NU = the number of frame units available for selection in
the sampling cell

• Characteristics of the population being sampled,
• Target reliability of the estimates,
• Survey design employed.

nS = the number of units sampled.
For example, if there are 100 frame units in a sampling cell
from which 5 units are selected for the sample, then the
weight assigned to each of the sample units would be 100
divided by 5, or 20.

One criterion of the SOII design is identifying target
estimation industries (TEIs). TEIs, which are selected by
each state, are North American Industry Classification
System (NAICS) industries or groups of industries for which
10

SOII Data Collection

In addition to the IDCF, employers have the option to
request, receive, and respond electronically to the SOII using
an automated fillable survey form. Other alternative methods
for satisfying the requirement to respond to the SOII include
a standardized fax form, telephone, and mail. Regardless
of which option an employer chooses for responding to the
SOII, each form has been designed to resemble employer
OSHA recordkeeping forms to allow for easy transcription.
On the SOII form, Section 1: Establishment Information
contains questions about the number of employee hours
worked (needed in the calculation of incidence rates) and the
reporting unit’s average employment. Section 2: Summary of
Work-Related Injuries and Illnesses asks employers to report
information on the number of injuries and illnesses by type
of case, which can be copied directly from employer injury
and illness logs. Section 3: Reporting Cases with Days Away
from Work requests detailed information on the worker and
the injury or illness for cases that resulted in at least one day
away from work, which can be copied from the employer’s
OSHA case forms. State agency and BLS personnel edit
the summary data (Section 2) and code the details (see
discussion of OIICS in Part I. Common Coding Systems) of
serious cases (Section 3), verifying and correcting apparent
inconsistencies by contacting the employer again. Section 4:
Contact Information asks the employer to provide contact
information for the individual who completed the survey
form in case there are discrepancies in the reported data that
require correction. Section 5: If You Need Help provides
employers with contact phone numbers within each state
should employers have questions or require assistance in
completing the survey form.
Survey responses received in the mail are manually keyed
into the SOII data collection system, while Internet responses
remove this manual processing since data are entered directly
by the employer in the IDCF and then uploaded into the SOII
data collection system. Therefore, Internet responses using
IDCF reduce processing time and remove the risk of errors
associated with the manual keying of data required of SOII
responses received in hard copy format (by mail). Similarly
for the automated fillable form, data that employers have
entered into the form are loaded directly into the SOII data
collection system. All reports that are received, regardless of
which reporting option was used, are electronically edited.
Reports that do not meet the computer screening criteria or
senior staff review are verified with the employer.
By midsummer, the active data collection phase of the SOII
is completed and the preparation of data for both national
and state estimates of occupational injuries and illnesses
begins. Annual summary estimates on injury and illness
incidence rates and counts by detailed industry and type
of case are now published in mid-October, compared with
mid-December in past years. A subsequent release covering
more detailed estimates of the case circumstances and worker
characteristics for injuries and illnesses that involved days
away from work now follows in early November, compared
with the following March or April in past years.

Although most of the SOII data are now collected
electronically, the SOII began as a mail-based survey. State
agencies mailed a printed survey form to selected employers
early in the year following the year for which employers were
required to record their injury and illness experience on the
OSHA recordkeeping forms. For establishments in those
states not participating in the program (see section on State
Participation in the SOII), survey forms were mailed by BLS.
Each employer completed and mailed back its survey form,
which was then manually keyed into a survey collection
system. Data from the surveys were used for both national
and state estimates of occupational injuries and illnesses. This
procedure eliminated duplicate reporting by respondents and,
together with the use of identical survey techniques at the
national and state levels, ensured maximum comparability of
estimates. (Links to SOII forms and their related instructions
are included in the section on SOII Forms.)
Collection methods for the SOII have evolved significantly
in recent years in response to BLS goals to collect data more
efficiently and to provide more timely and accurate data to its
users. Use of new technology—namely the Internet and other
electronic resources as alternative means for responding
to the SOII—has reduced data collection and processing
times. The result has been more timely publication of SOII
estimates. Options that are available to employers to meet
their requirement to respond to the SOII include the following:
• Internet
• Automated fillable form
• Fax form
• Telephone
• Mail
Establishments selected to participate in the SOII are notified
by BLS in writing in advance of the year for which they will
be required to provide data. This notification process ensures
that even those establishments not normally required by
OSHA to maintain injury and illness logs and case forms will
do so for the survey year.
The Internet Data Collection Facility (IDCF) is the
centralized data collection facility for BLS, used by the
SOII and other BLS programs as a platform for Internet data
collection. The facility provides a uniform, manageable,
and secure environment for BLS survey collection via
the Internet. BLS first used the IDCF for the 2002 survey
year. The IDCF survey instrument is a Web-based tool that
provides sampled employers the ability to respond to the
SOII using online capabilities. Employers can enter their
injury and illness data, along with employment and hours
worked, using an Internet-based system that is designed to
resemble as closely as possible the hard copy survey forms
that employers traditionally received and responded to by
mail. By the 2009 survey year, around 70 percent of total
responses were submitted by IDCF.

11

establishments may be prenotified of their obligation
to maintain logs throughout the year. As a result, the
universe file from which the sampling frame was
developed is not current to the reference year of
the survey, making it necessary to adjust the data
before publication to reflect current employment
levels. This procedure is known as benchmarking.
For the SOII, all estimates of totals are adjusted
by benchmark factors (BMF) at the state, industry,
and ownership level, and at the national, industry,
and ownership level as well. The benchmarking
procedure requires a source of accurate employment
data which can be converted into annual average
employment figures at the industry level for which
separate estimates are desired. The SOII uses
employment data primarily derived from the BLS
Quarterly Census of Employment and Wages.

SOII Estimation Procedures

Nonfatal workplace injury and illness data collected for the
SOII are used to tabulate estimates for two separate data
series—annual summary (industry-level) estimates and
more detailed case circumstance and worker characteristic
estimates for cases that involved days away from work. Part
of the estimation process involves weighting sample units
and cases to represent all injuries and illnesses from units
on the frame from which the sample was selected. Sample
unit and case weighting and calculation of incidence rates are
described in the sections that follow.
Weighting for Summary Estimates
Original summary weight. By means of a weighting
procedure, sample units represent all units in their state,
industry, employment size class, and ownership (private
sector, state government, or local government), also referred
to as a sampling cell. An original summary weight for each
sample unit is determined by the inverse of the sampling ratio
(number of units selected relative to the number of frame
units available for selection) for the sampling cell from which
the unit was selected. (See example in SOII Sample Design
section.)

•

Final summary weight. Prior to the tabulation of summary
estimates, the original summary weight for a sample unit is
adjusted by numerical factors to account for nonresponse
from some sample units, benchmarking the sampling frame
to the current survey year, and occasional inability for some
sample units to report data for the unit as it was sampled. A
final summary weight used in the tabulation of estimates is
determined by applying these factors to the original weight:
•

•

•

Reaggregation—Because there are occasional
instances when a sample unit may be unable to report
data for the unit as it was sampled, adjustments are
made to account for these situations by applying a
reaggregation factor (REAG) to the unit’s original
summary weight. For example, a sample unit that
was involved in a merger may report data covering
both the original sample unit and the unit or units
with which it merged, requiring an adjustment to the
weight to account for the additional unit included in
the reported data.

Therefore, the final summary weight for a sample unit is
determined by the product of the original summary weight
and these three factors, or

Unit nonresponse—Because a small proportion of
SOII forms are not returned, weights of responding
employers in a sampling cell are adjusted to account
for nonrespondents by applying a nonresponse
adjustment factor (NRAF).

Final summary weight = Original summary weight × NRAF
× OAF × BMF × REAG.
Weighting for Case and Demographic Estimates
Days away from work cases. Each case involving days away
from work is weighted by the respective sample unit’s final
summary weight with which it is associated. In addition, the
final summary weight that is applied to each case is adjusted
for several factors to ensure that the number of usable cases
that have been submitted are equal to the days away from
work cases used in the tabulation of summary estimates.
These factors are used to adjust for case subsampling
(see section on the SOII Sample Design for discussion of
subsampling) and case nonresponse for those establishments
that did not provide information on all cases involving days
away from work which occurred in their establishment in the
survey year.

Outlier—An outlier adjustment factor (OAF) is
applied when an establishment experiences a rare
circumstance that makes its case count or hours
worked unrepresentative of its sampling cell. 
Including such data with the original sampling weight
would have an undue influence on the estimates. For
example, an establishment may report an unusually
high number of illness cases that occurred as a result
of a severe and uncommon scabies outbreak.  The
outlier adjustment factor adjusts the unit’s weight to
one to avoid an overrepresentation of this uncommon
occurrence. An adjustment factor to distribute the
remaining weighted employment of the outlier unit
is also applied to each of the remaining useable units
in the sampling cell.

• Case Subsampling Factor (CSSF) —CSSF is applied
at the establishment level to adjust for instances in
which the number of usable days away from work
(DAFW) case forms that are submitted differ from

Benchmarking—The sample for a particular survey
year must be drawn prior to that year, so that selected

12

the number of DAFW cases that are reported on the
summary. For example, 15 case forms are submitted
and are usable, but 39 DAFW cases are reported on
the sample unit’s summary. This CSSF is designed
to weight the number of DAFW cases for which
usable data were reported to equal the total number
of DAFW cases indicated on the summary (that is,
the number of DAFW cases that the establishment
experienced). A maximum threshold is applied to
this factor, beyond which further adjustments are
accomplished through other factors described below.
The CSSF is the ratio of DAFW cases reported on
the summary to the number of DAFW cases for
which data were submitted, or
���� � �

Incidence rate calculation
Incidence rates are calculated using the total case counts
obtained through the weighting and benchmarking procedures
described above. The adjusted estimates for a particular
characteristic, such as injury and illness cases involving days
away from work, are aggregated to the appropriate level of
industry detail. The total is multiplied by 200,000 for injuries
and illnesses combined and for injuries only (that is, 40
hours per week multiplied by 50 weeks—the base of hours
commonly regarded as worked by 100 full-time employees
during a calendar year). The product is then divided by the
weighted and benchmarked estimate of hours worked as
reported in the SOII for the industry segment. The formula
for calculating the incidence rate at the lowest level of
industry detail is

�������ses��summ����

�������ses��submitted�..

…‹†‡…‡ƒ–‡ ൌ 

• Case Nonresponse Adjustment Factor (CNRAF)
The CNRAF is applied at the sampling cell level.
This factor is applied after the CSSF in instances
where the CSSF failed to adequately adjust reported
summary DAFW cases to equal the submitted usable
DAFW cases for a sampling cell. The CNRAF is
designed to adjust for cases that were not reported
as a result of nonresponse within the sampling cell.
A maximum threshold is applied to this factor,
beyond which further adjustments are accomplished
through the CRAF discussed below. The CNRAF is
calculated as

Incidence rates for higher levels of industry detail are produced
using aggregated weighted and benchmarked totals. Incidence
rates may be computed by industry, employment size, state,
various case circumstances, and select worker characteristics.
Incidence rates for illnesses and for case and worker
characteristic categories are published per 10,000 full-time
employees, using 20,000,000 hours instead of 200,000 hours
in the formula shown above. (The 20,000,000 hours refers
to 10,000 full-time employees working 40 hours per week,
50 weeks per year.) Incidence rates per 10,000 workers can
be converted to rates per 100 workers by moving the decimal
point left two places and rounding the resulting rate to the
nearest tenth.

‫ܹܵܨ‬
ቀ
ቁ  ൈ ‫•‡•ƒ…ܹܨܣܦ‬ሺ•—ƒ”›ሻ
‫ܨܯܤ‬
‫ ܨܣܴܰܥ‬ൌ ȭ
‫ܹܵܨ‬
ቀ
ቁ  ൈ ‫ ܨܵܵܥ‬ൈ ‫•‡•ƒ…ܹܨܣܦ‬ሺ—•ƒ„Ž‡ሻ
‫ܨܯܤ‬

where:

Reliability of SOII Estimates
Estimates from the SOII are based on a scientifically
selected probability sample, rather than a census of the
entire population. (See section on SOII Sample Design.)
Sampling methodology makes it possible to collect data from
a sample from which inferences can be made regarding the
characteristics of the population from which the sample was
selected. These sample-based estimates may differ from the
results obtained from a census of the population. The sample
used for the SOII was one of many possible samples, each of
which could have produced different estimates. The variation
in the sample estimates across all possible samples that
could have been drawn is measured by the relative standard
error (RSE), which is used to calculate a confidence interval
around a sample estimate.
The 95-percent confidence interval is the interval centered
on the sample estimate and includes all values that are within
1.96 times the estimate’s standard error. If several different
samples were selected and used to estimate a population value
(such as injury and illness incidence rates), the 95-percent
confidence interval would include the true population value
approximately 95 percent of the time.

•

FSW = Final summary weight

• BMF = Benchmark factor
• CSSF = Case subsampling factor.
•

Case Ratio Adjustment Factor (CRAF) —The CRAF
is applied after both the CSSF and CNRAF factors
have been applied but have failed to adjust for missing
cases. The CRAF is applied at the estimation cell level
(target estimation industry and size class). The CRAF is
calculated as

‫ ܨܣܴܥ‬ൌ 

where

ሺܵ‫݀݁ݐݎ݋݌݁ݎݏܿ݅ݐݏ݅ݎ݁ݐܿܽݎ݄݂ܽܿ݋݉ݑ‬ሻ ൈ ʹͲͲǡͲͲͲ

ܵ‫݀݁݇ݎ݋ݓݏݎݑ݋݄݂݋ݎܾ݁݉ݑ݂݊݋݉ݑ‬

‫ ܹܵܨ‬ൈ ‫•‡•ƒ…ܹܨܣܦ‬ሺ•—ƒ”›ሻ
‫ ܹܵܨ‬ൈ ‫ ܨܵܵܥ‬ൈ ‫ ܨܣܴܰܥ‬ൈ ‫•‡•ƒ…ܹܨܣܦ‬ሺ—•ƒ„Ž‡ሻ

• FSW = Final summary weight
• CSSF = Case subsampling factor
• CNRAF = Case nonresponse adjustment factor.
13

For case circumstances and worker characteristics,
estimates are rounded to the nearest ten and are suppressed if
one of the following situations occurred:

For example, in 2006 the total injury and illness case
incidence rate for Nursing care facilities (NAICS 6231) was
9.8 cases per 100 full-time workers, or an estimated RSE of 2
percent. Hence, we are 95-percent confident that the interval
between 9.4 and 10.2 (or 9.8 ± (1.96 × 9.8 × 0.02)) includes
the true value of the incidence rate for total recordable injury
and illness cases in Nursing care facilities in 2006.
All estimates derived from a sample survey are subject to
sampling and nonsampling errors. Sampling errors occur
because observations are made on a sample, not on the entire
population. Percent-relative standard errors, which are a
measure of the sampling error in the estimates, are calculated
as part of the SOII estimation process. Both the estimates
and the percent-relative standard errors of the estimates (or
statistical models for approximating those relating to case
circumstances and worker characteristics) are published in
appendix A to the annual BLS bulletin Occupational Injuries
and Illnesses: Counts, Rates, and Characteristics.
Nonsampling errors in the estimates can be attributed to
many sources. Some examples are the inability to obtain
information about all cases in the sample, mistakes in
recording or coding the data, or definitional difficulties.
Although not measured, nonsampling errors will always occur
when statistics are gathered. To minimize the nonsampling
errors in the estimates, standard procedures are applied to
each respondent’s information, the completed survey forms
are systematically edited, and apparent inconsistencies are
verified with the employer.

• The number of cases is fewer than 15.
• The number of cases is 15 or greater and the relative
standard error for the estimate exceeds a specified
limit.
Presentation of SOII Estimates
Each year, BLS publishes national estimates for private
industry, state government, and local government from
the SOII in two news releases—a summary of counts and
incidence rates of nonfatal workplace injuries and illnesses,
followed shortly thereafter by a more detailed release
describing the injury and illness cases that involved days
away from work. Tables containing nearly all available
estimates are published on the Internet in conjunction with
these news releases. For some years, a comprehensive
report produced jointly by the SOII and the Census of
Fatal Occupational Injuries (CFOI) is produced later in the
year. This report features charts and text highlighting fatal
occupational injury data, nonfatal industry summary data,
and nonfatal case circumstances and worker characteristics
data. SOII estimates can also be accessed through a number
of electronic resources. Among these is the Profiles on the
Web system, which allows users to create customized tables
based on user-specified criteria. Profiles can be created both
for annual summary estimates and for case circumstance
and worker characteristic numbers or rates from the SOII.
Employers can also use an Incidence rate calculator and
comparison tool to calculate their establishment’s incidence
rates, which are then compared directly to the incidence rates
from the SOII for their respective industry.
SOII estimates also are presented periodically in articles
published in two BLS journals—Monthly Labor Review
and the online Compensation and Working Conditions. The
data are also available on CDs and on the Internet at http://
www.bls.gov/iif/oshcont1.htm. The data are also published
in private safety and trade journals. In addition, state data
through 1987 are available on microfiche from the National
Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161. A list of states (including telephone
numbers) that can provide more current state estimates is
available from the BLS Office of Safety, Health, and Working
Conditions at (202) 691-6170, or the list can be accessed
online at http://www.bls.gov/iif/oshstate.htm.
Flat files containing all SOII estimates are available through
FTP (file transfer protocol) from the BLS FTP webpage. Each
data series on the BLS FTP site includes a two-character
series designator. Clicking on the series designator expands
the directory to provide a list of the files included with each
series. Included with each series (generally the last file in
each series directory) is a text file that provides: (1) a survey
definition and a listing of the FTP files listed in the survey
directory; (2) time series, series file, data file, and mapping

Publication Guidelines for SOII Estimates
Nonfatal occupational injury and illness estimates were
published for more than 1,200 NAICS industries (including
aggregates) in 2010—including select industries within state
and local government, which were published for the first
time for the 2008 survey year. Data for the SOII are collected
under a strict pledge of confidentiality that these data will be
used solely for statistical purposes and will not be disclosed
for other purposes. The number of publishable industries may
vary from year to year, depending on the number of industries
that fail to meet publication guidelines. Industry estimates
may not be published if one of the following situations exists:
• Publication might disclose confidential information.
• The relative standard error of the estimate for days
away from work, job transfer, or restriction cases for
the industry exceeds a specified limit.
• The benchmark factor for the industry falls outside
an acceptable range.
Data for an unpublished industry are included in the total for
the aggregate industry level of which it is a part. Also, selected
estimates are suppressed within publishable industries if the
relative standard error for the estimate exceeds a specified
limit.

14

comparability of SOII estimates. Therefore, SOII estimates
for 2002 may not be comparable to estimates for other years.
As discussed in Part I. Common Coding Systems, industry
and occupation classification systems used in the stratification
of SOII estimates also changed in 2003. Owing to the
significant differences when compared with prior industry and
occupation classification systems, caution should be exercised
when attempting to compare estimates from 2003 forward
with estimates from prior years. Similarly the 2011 change
in OIICS, leads to caution when comparing estimates from
2011 forward with estimates from prior years. The section on
Technical References later in this chapter references articles
that discuss the influence of changes in coding systems used
for SOII estimates. SOII estimates published by BLS are in
the public domain and, with appropriate credit, may be used
without explicit permission from BLS.

file definitions and relationships; (3) series, data, and
mapping file formats and definitions; and (4) a data element
directory. The SOII series have experienced several breaks
due to changes in coding systems. Data from these separate
series may not be comparable to one another. Consequently,
the following FTP series identifiers cover available SOII data
reflective of these series breaks:
• SOII - Summary data series:
• hs —1976–1988 (1972 SIC)
• sh —1989–2001 (1987 SIC)
• si —2002 (New OSHA recordkeeping)
• ii —2003 forward (2007 NAICS)
• SOII - Case and demographics data series:
• cd —1992–2001 (1987 SIC)
• hc —2002 (New OSHA recordkeeping)
• ch —2003 forward (2007 NAICS)
• cs – 2011 forward (OIICS 2.0)

Survey Forms

Various forms for the SOII can be downloaded from http://
www.bls.gov/respondents/iif/forms.htm. Included on this
page are links to the following:

Uses and Limitations of SOII Estimates
National and state policymakers use SOII estimates as an
indicator of the magnitude of and trends in occupational safety
and health problems. The Occupational Safety and Health
Administration (OSHA) uses the statistics to help measure
the effectiveness of its enforcement and outreach programs
in reducing work-related injuries and illnesses. Both labor
and management use SOII estimates in evaluating safety
programs. Other users include insurance carriers involved in
workers’ compensation, industrial hygienists, manufacturers
of safety equipment, researchers, and others concerned with
job safety and health.
Many factors can influence counts and rates of injuries
and illnesses in a given year. These include not only the
year’s injury and illness experiences but also employers’
understanding of which cases are work-related under current
OSHA recordkeeping guidelines. The number of injuries
and illnesses reported in a given year also can be affected by
changes in the level of economic activity, working conditions
and work practices, worker experience and training, and the
number of hours worked.
Each year, the SOII measures the number of new workrelated illness cases which are recognized and reported. But
some conditions, such as long-term latent illnesses caused
by exposure to carcinogens, often are difficult to associate
with the workplace and are not adequately recognized and
reported, and therefore are believed to be understated in the
SOII. In contrast, the overwhelming majority of the reported
new illnesses are those which are easier to directly link to
workplace activity (such as contact dermatitis or carpal
tunnel syndrome).
Two relatively recent changes have had an impact on
the SOII, and these changes may limit comparability of
data series. The first change involves recordkeeping. New
recordkeeping guidelines were introduced by OSHA,
effective January 1, 2002. Definitional changes between
current and previous recordkeeping guidelines may limit the

•
•

•
•

•
•

Notification of the Requirement to Participate in the
SOII
OSHA recordkeeping forms:
• Form 300 (Log of work-related injuries and
illnesses)
• Form 300A (Summary of work-related injuries
and illnesses)
• Form 301 (Injury and illness incident report)
Instructions for responding electronically to the
SOII using BLS Internet Data Collection Facility
(IDCF) —BLS-9300-IDCF
SOII forms:
• An automated fillable SOII form—BLS9300-N06
• A nonfillable SOII form—BLS-9300-N06
(similar to mail-in form)
• A
Spanish-language
SOII
form—
Encuesta Sobre Lesiones y Enfermedades
Occupacionales (Form BLS-9300 N06)
A FAX response form —BLS-9300 FAX
An electronic options brochure, explaining the
different electronic methods that respondents can
use to satisfy their requirement to respond to SOII.

Additional instructions for responding to the SOII are
available online at http://www.bls.gov/respondents/iif/
instructions.htm.

Part III. Census of Fatal
Occupational Injuries
Since 1992, the Census of Fatal Occupational Injuries
(CFOI) has collected and published a comprehensive
count of work-related fatal injuries and descriptive data on
their circumstances. CFOI counts are especially accurate
15

because the census uses multiple data sources (such as death
certificates, state workers’ compensation records, news
media, OSHA reports) to identify work-related fatal injuries.
Complete and reliable counts of fatal work injuries and
how they occurred enable the safety and health community
to identify and track specific life-threatening hazards, such
as work-related homicides in retail stores and construction
workers struck and fatally injured by highway vehicles
and equipment. In 1994 and 1995, several groups of safety
experts, including the National Safety Council and the
National Center for Health Statistics, endorsed the CFOI as
the official count of work-related fatalities, in preference to
other, less comprehensive measures.

different organizations at that time varied greatly from 3,000
to 11,000 deaths nationally per year.7
The CFOI approach to compiling data on fatal work injuries
was initially tested in a BLS cooperative effort with the
Texas Department of Health during 1988. That study, which
collected fatality data retrospectively for 1986, highlighted the
need for multiple data sources and the feasibility of matching
fatalities and their circumstances across those sources.8 This
approach was tested again in Texas and Colorado in 1990,
with results confirming that the same kind of data could be
obtained from multiple data sources on a current basis.9 The
CFOI program was initially implemented in 32 states and
New York City in 1991 and expanded to cover all 50 states
and the District of Columbia in 1992. As of 2011, the U.S.
territories Puerto Rico, Virgin Islands, Guam, and America
Samoa are also included.

Background
Since 1992, CFOI data have supplanted the limited
information on fatalities that had been available since 1972
from the SOII. The CFOI covers not only private, state
government, and local government wage and salary workers
covered in the SOII, but also workers on small farms, the
self-employed, family workers, and federal government
workers not covered by the survey. Unlike CFOI data, the
SOII’s fatality estimates cover only establishments with more
than 10 employees and, for purposes of statistical reliability,
were combined into a 2-year average before a distribution
of fatalities by the associated event or exposure could be
published.
The seeds for the CFOI were sown by the National Academy
of Sciences and other safety and health organizations in the
late 1980s, when they recommended obtaining complete and
timely counts and detailed circumstances of fatal workplace
injuries so that policymakers could develop and more
effectively implement safety initiatives. Some of those expert
recommendations mentioned using multiple data sources
such as death certificates and workers’ compensation reports
to identify and profile fatal work injuries for all workers. More
specifically, the Keystone Dialogue Group recommended
the development of a consensus method for counting workrelated fatalities,6 stating that the “development of an accepted
count of workplace deaths should mute controversy on this
issue stemming from the variety of estimates coming from
different sources.” In this regard, fatality estimates made by

CFOI Definitions

For a fatality to be included in CFOI, the decedent must
have been self-employed, working for pay, or volunteering
at the time of the event, engaged in a legal work activity, and
present at the site of the incident as a job requirement.10 These
criteria are generally broader than those used by federal and
state agencies administering specific laws and regulations.
Fatalities that occur during a person’s normal commute to or
from work are excluded from CFOI counts.
An occupational injury is defined as any wound or damage
to the body resulting from acute exposure to energy, such as
heat, electricity, or impact from a crash or fall, or from the
absence of such essentials as heat or oxygen, caused by a
specific event or incident within a single workday or shift.
Included are open wounds, intracranial and internal injuries,
heatstroke, hypothermia, asphyxiation, acute poisonings
resulting from short-term exposures limited to the worker’s
shift, suicides and homicides, and work injuries listed as
underlying or contributory causes of death.
Because of the latency period of many occupational
illnesses and the resulting difficulty associated with linking
illnesses to work, it is difficult to compile a complete count
of all fatal illnesses in a given year. Thus, information on
illness-related deaths is excluded from the basic CFOI count.
Over 30 data elements are collected, coded, and tabulated
in the CFOI, including information about the worker and the
circumstances surrounding the fatal incident. Some of the
elements collected include the following:

• Case circumstances

6
See the Keystone Center’s final report, “Keystone National Policy
Dialogue on Work-Related Illness and Injury Recordkeeping,” (Keystone,
CO, January 1989). For an account of various attempts to count fatalities at
work, see Dino Drudi, “The evolution of occupational fatality statistics in the
United States,” Compensation and Working Conditions, July 1995, pp. 1–5.
7
See BLS Survey of Occupational Injuries and Illnesses (1972–91); the
National Safety Council Accidents Facts; and the National Institute for
Occupational Safety and Health’s National Traumatic Occupational Fatality
Study A Decade of Surveillance, 1980–1989.
8
See Janice Windau and Donna Goodrich, “Testing a census approach to
compiling data on fatal work injuries,” Monthly Labor Review, December
1990, pp. 47–49. The study also found that, for verification purposes,
timeliness is important in maximizing respondents’ recall and in reducing
the number of those failing to respond because they have relocated.

•
•
•
•
•

Nature of injury
Part of body affected by injury
Source of injury
Event or exposure
Secondary source of injury

9
See Guy Toscano and Janice Windau, “Further testing of a census
approach to compiling data on fatal work injuries,” Monthly Labor Review,
October 1991, pp. 33–36
10
See http://www.bls.gov/iif/oshcfdef.htm for more information on work
relationship criteria.

16

Date of birth
Date of death
Date of incident
Worker characteristics
• Occupation
• Age
• Race or ethnic origin
• Country of foreign birth (if applicable)
• Gender
• Length of service with employer
• Employee status (wage and salary, self-employed, family
business)
• Establishment employment size
•
•
•
•

(that is, whether a fatality is work-related) be substantiated
by two or more independent source documents or a source
document and a follow-up questionnaire. Follow-up
questionnaires are sent either to the employer or to another
contact that has knowledge of the incident. The followup questionnaire is also used to collect information that
may be missing from the source documents. In the case of
nonresponse to the questionnaire or inconsistent data results,
further follow-up by telephone is required. At the end of
the collection period, fatal injuries for which the state has
only one source document are reviewed by BLS. The case
is included in the national database only if the state and BLS
agree that there is sufficient information on the sole source
document to determine that it is indeed work-related.

• Industry of employer

CFOI Measures

• Location type (farm, street, warehouse, etc.)

The CFOI provides annual fatal injury counts by case
circumstances and worker characteristics highlighting the
number of worker fatalities for the following:

• Medical complication (if any)
• Narrative of how incident occurred
• Ownership (private sector or state, local, or federal
government)
• State of injury/death
• Time of incident (month, day of week, time of day)
• Time workday began
• Worker activity (driving a vehicle, tending a store, etc.)

CFOI Collection Methods

The Census of Fatal Occupational Injuries (CFOI) is a
cooperative venture in which the operating costs are shared
equally between the state and federal governments. Each
year, states are responsible for data collection, follow-up,
and coding on a timely basis. Preliminary CFOI data are
generally released approximately 8 months after the close
of the reference year. Revised and final CFOI data are
generally released approximately 16 months after the close
of the reference year. Data elements are coded according to
standard CFOI instructions.
States obtain information on fatal work injuries from
a number of different sources. Among these are death
certificates marked injury at work, workers’ compensation
reports, and other reports provided by state administrative
agencies. Additional information provided to states originates
from federal agencies, such as the U.S. Department of Labor’s
Occupational Safety and Health Administration (OSHA),
Office of Workers’ Compensation Programs (OCWP), and
Mine Safety and Health Administration (MSHA). Overall,
state agencies collect more than 20,000 individual source
documents each year or about an average of four documents
from different sources for each fatal injury. To avoid
duplication in the counts, source documents are matched
using the decedent’s name and other information.
To ensure an accurate count of fatal occupational injuries,
the CFOI requires that, for each case, the work relationship

•

Industry by selected event or exposure

•

Industry by transportation incident and homicide

•

Industry by worker status

•

Primary and secondary source by major private
industry division

•

Occupation by event or exposure

•

Occupation by transportation incident and homicide

•

Worker characteristics (worker status, gender, age,
race or ethnic origin) by event or exposure
• Event or exposure by age
• Event or exposure by major private industry sector

In addition to counts, percent distributions of workers
who were fatally injured are available by selected case
circumstance and characteristics of the deceased, including
the following:
• Event or exposure
• Industry and selected event or exposure
• Occupation and selected event or exposure
• Selected worker characteristics and selected event
or exposure
• State and selected event or exposure

Fatal Injury Rates
Fatal injury rates depict the risk of incurring a fatal
occupational injury faced by all workers or a subgroup of
workers and are used to compare risk over time or with other
worker groups. Workers can be grouped for comparison
by a number of variables, including industry, worker age,

17

or gender. Since employment data are not collected by the
CFOI, fatal injury rates are calculated using estimates of
hours worked from the Current Population Survey (CPS).
In 2008 the CFOI adopted hours-based employment as
the denominator of fatal injury rates to measure fatal injury
risk. This methodology is generally considered to be more
accurate than employment-based rates per the standardized
length of exposure to risk of occupational injury. It is defined
as the average number of workers at work over the year
multiplied by the average hours each employee works over
the year. More information on the change from employment
to hours-based fatal injury rates is available online at http://
www.bls.gov/iif/oshnotice10.htm.

State Rates
Unlike at the national level, “at work” and “average hours”
data are not available at the state level. State rates by industry
can be imputed by using national-level “average hours” and
“at work” information to calculate the total annual number of
hours for each worker group.
The rate represents the number of fatal occupational
injuries per 100,000 full-time equivalent workers and was
calculated as

where:  

•
•

The imputation to calculate EHS (total hours worked by
all employees during the calendar year) for the state was
calculated as

where:
•
•
•

EH = AW × H
•

•

ES = employment in the state
HWN = average annual number of hours for
each employee in a group nationally.
The N subscript denotes a national number; an S subscript denotes a state number.

AWN × HN= (139,824,000 ×1,945) =271,957,680,000= EHN
(total hours for the year).

(N/EH) X 200,000,000
•
•

‫ܪܧ‬௦ ൌ ‫ܹܪ‬ேൈ ‫ܧ‬௦

Examples
For the national rates, compute N/EH × 200,000,000. To get
EH, the total hours, multiply “at work” and “average hours.”
This first step involves the shaded area in table 1 on page
19 (columns B, C, and D in table). So to get the national
denominator:

EH = total hours worked by all employees
in a group during the calendar year
• AW = at work (number of employees
working in a group)
• H = average hours (average annual hours
worked by an employee in that group).
The hours-based rate (expressed per 100,000 workers) is

where:

NS = the number of fatal work injuries in the
state
EHS = total imputed hours worked by all employees in the state
200,000,000 = base for 100,000 equivalent
full-time workers (working 40 hours per
week, 50 weeks per year).

•

National Rates
To accurately describe fatal injury risk for a worker group,
the numerator (fatal injuries) and denominator (total hours
worked) of the rate must refer to the same group of workers.
The hours-worked data from the CPS used in the rate
calculations do not include workers under the age of 16,
volunteers, and members of the resident military. Therefore,
fatal injuries occurring to these workers are also excluded
from the numerator.
National fatal injury rates use data from the CPS. As
opposed to the employment number, data on persons “at
work” exclude persons who were temporarily absent from
a job (classified in the zero-hours-worked category, “with a
job but not at work”). Those not at work were absent from
their jobs for the entire week for such reasons as bad weather,
vacation, illness, or involvement in a labor dispute. Two
estimates, “at work” and “average hours,” are combined to
create the denominator, annual total hours worked,
where:

(�� ⁄��� ) Χ 200,000,000

Then take the total number of fatal injuries in 2008, 5,084
(5,214 minus the number of workers under the age of 16,
volunteers, and members of the resident military), and divide
by EHN and multiply by 200,000,000:

N = number of fatal injuries in a group
EH = total hours worked by all employees
in a group during the calendar year
200,000,000 = base for 100,000 equivalent
full-time workers (working 40 hours per
week, 50 weeks per year).

(5,084/271,957,680,000) × 200,000,000=3.7.

18

For the state rates, the shaded information is not available,
so to impute the state average hours, divide the national total
hours (column D) by the national employment (column A) to
get the average annual number of hours per employee (HWN,
column E, is the imputed number).
Then multiply this by the state employment to get the
denominator. So the state rate calculation is as follows:

ages, plus resident military figures derived from
the U.S. Department of Defense).
Fatality rate = (5,711/142,894,000) x 100,000 = 4.0 fatalities per 100,000 workers.
Comparison of National and State Rates Caveat
State industry rates are not directly comparable to national
industry rates. Because state rates include government workers in their respective industry sector and are not broken out
separately, both the numerator and denominator include a different group of workers than that of the national rates.
If a user decides to add up all the states in one industry
and average out their rates to compare it to the national
average, they will not get the national average due to this
data difference, with the all-ownership/state rates most likely
being slightly higher because of the added fatal injuries and
different employment data.

Employment
(in thousands) Fatalities NS
ES
California Total
17,045
448
California Construction
1,294
67
State

Then multiply this by the state employment to get the
denominator. So the state rate calculation is as follows:
NS /(ES × HWN ) × 200,000,000

CPS Data Limitations
There are a number of limitations to these fatal injury rates:

448/(17,045,000 ×1,871) × 200,000,000=2.8
CFOI Rates Prior To 2008
All the CFOI fatal injury rates published by BLS for the
years 1992 through 2007 were employment-based rates and
measured the risk of fatal injury for those employed during
a given period of time, regardless of hours worked. The
following is the formula for calculating a fatality rate from
1992 through 2007:

•

The CPS data used to calculate rates are estimates
based on a sample rather than a complete count.
Therefore, the CPS estimates and fatality rates have
sampling errors. The rates calculated using the CPS
may differ from those that would have been obtained
from a census of employed persons. See Explanatory
Notes and Estimates of Error in the February 2004
Employment and Earnings for an explanation of CPS
sampling and estimation methodology, and standard
error computations. The relative standard errors of the
CPS estimates can be used to approximate confidence
ranges for the fatality rates.

•

The CPS categorizes workers according to their primary
job, which may differ from the job the deceased was
working in when fatally injured, as reported in the
CFOI.

•

The annual average of hours worked represent total
hours at work for CPS respondents, including those

�⁄�� � �������

where:
•  N = the number of fatally injured workers,
16 years and older
• W = the number of employed workers, 16
years and older.
For example, in computing the 2005 national fatality rate:
N = 5,734 - 23 workers under age 16 = 5,711 (from 2005
CFOI)
W = 142,894,000 (from CPS, 2005 annual averTable 1.
A

B

Industry

Employment
(in
thousands)
EN

At work
(Employment in
thousands)
AWN

Total
Construction

145,362
10,974

139,824
10,558

C
Avg. Annual
Hours
(Weekly
Hours x 50)
HN
1,945
1,980

Source Data 2008: National, all ownerships

19

D

E

Total Hours
(Annual, in
thousands)
EHN=AWN*HN

Adjustment
(Annual Total Hours,
per employee)
HWN = EHN / EN

271,957,680
20,904,840

1,871
1,904

that work more than one job. Total hours worked for
respondents with multiple jobs will be recorded in the
occupation and industry of the primary job.
•

publication, Compensation and Working Conditions,
and occasionally in the Monthly Labor Review or other
publications. A research microdata file that is useful for
safety researchers and others involved in promoting safety in
the workplace can be obtained through a letter of agreement
with BLS to protect the confidentiality of data.11
Flat files of estimates from the entire CFOI database or
parts of the database are available through FTP (file transfer
protocol) from the BLS FTP Webpage. Each dataset on the
BLS FTP site includes a two-character series designator.
Clicking on the series designator opens a list of the files
included with each series. Included with each (generally the
last file in each list) will be a text file that explains what each
data set covers, the variables included in each set, naming
conventions, variable field lengths in the flat file, etc. The
CFOI series experienced a break in 2003 due to changes
in industry (SIC to NAICS) and occupation (SOC) coding
systems. The CFOI series experienced another break in
2011 due to changes in the Occupational Injury and Illness
classification system (OIICS) to OIICS 2.0. Data from
these different series may not be comparable to one another.
Consequently, the following FTP series identifiers cover
available CFOI data reflective of these series breaks:

Rates are calculated at the level of detail available from
the CPS data. Additionally, rates are only calculated for
those occupations and industries which met minimum
thresholds of having at least 15 fatal injuries and 20,000
employed.

Presentation of CFOI Data
Summary information including the key fatal injury
circumstances (event/exposure, occupation, and industry)
and the demographics of workers fatally injured on the job,
along with overall counts, are included in a national news
release issued about 8 months after the end of the reference
period. Supplementary tables containing fatal injury
rates and special profiles of specific fatal events (such as
highway incidents and homicides) also are available with
the news release. Besides national data, state-specific data
on workplace fatalities are available from participating state
agencies. A list of state agencies along with their telephone
numbers is available from BLS at (202) 691-6170 or online
at http://www.bls.gov/iif/oshstate.htm.
As with estimates from the SOII, the Profiles on the Web
system allows users to create customized tables of the number
of work-related fatal injuries based on user-specified criteria.
The CFOI also produces a joint report with SOII featuring
charts and text highlighting fatal injury data, nonfatal industry
summary data, and nonfatal case circumstances and worker
characteristic data.
Articles and detailed tables containing both national
and state data are published regularly in the BLS online

• CFOI data series:

• cf—1992–2002 (1987 SIC)
• fi—2003–2010 (2002 NAICS)
• fw—2011 forward (OIICS 2.0)

Uses and Limitations of CFOI Data
CFOI data help safety and health experts to monitor the
number and types of deadly work injuries over time and to
focus on work settings that have particularly high risks, such
as robbery-related homicides in retail stores, constructionrelated fatalities, and drownings in the commercial fishing
industry.12 Fatal injury profiles can be generated from the
CFOI database for specific worker groups (such as the selfemployed or female workers), for certain types of machinery
(such as farm equipment), and for specific fatal circumstances
(such as work activities at the time of fatal contact with
electric current). Such profiles help identify existing work
standards that may require revision and highlight safety
problems where intervention strategies need to be developed.
Although states are using about two dozen independent
data sources to identify and substantiate work-related
fatalities, there are some fatal injuries at work that are missed
by the CFOI. Some unidentified work-related fatal injuries
undoubtedly occur on farms, at sea, and on highways, to
cite three examples. BLS and its participating state partners
continue to seek new ways of verifying work-related fatal

11
BLS may approve access to an offsite CFOI microdata research file. The
CFOI research file contains data from various sources. Some of these data
are collected under a pledge of confidentiality and therefore are protected
under the Confidential Information Protection and Statistical Efficiency Act
of 2002 (CIPSEA). The CFOI research file is available only to researchers
who agree to protect the confidentiality of the data and have the safeguards
in place to do so. In addition, proposed projects must have a well-defined
research question of scientific merit that is of a purely statistical nature.
Ultimately, final approval for access to this file rests with the Commissioner
of BLS. Upon approval, BLS will prepare a Letter of Agreement which
must be signed by the Commissioner of the Bureau of Labor Statistics
and an official of the recipient’s organization, such as a President, Vice
President, Provost, Director of Sponsored Research, Director of Contract
and Grant Administration, or similar official, prior to release of the CFOI
research file. By signing the Letter of Agreement, the researcher and the
researcher’s organization agree to adhere to BLS confidentiality policy as
applicable to the CFOI research file. In addition, all individuals who will
have access to the CFOI data must sign an Agent Agreement acknowledging
their understanding of BLS confidentiality policy prior to accessing the
CFOI data. Applications can be submitted at any time but are processed
twice a year. Deadlines for processing are March 15 and September 15.
Applications received after these dates will not be processed until the next
application deadline. The application review process takes approximately
8 to 10 weeks. The application can be downloaded online at ftp.bls.gov/
pub/special.requests/ocwc/osh/cfoi_app.zip. (For information on viewing
ZIP files, see http://www.bls.gov/bls/blszip.htm.) Before submitting an
application, please contact us at [email protected] or call us at 202-6916170 to discuss your project. Procedures for obtaining access to the research
file can be found here: http://www.bls.gov/iif/cfoi_offsite.htm.

12
See, for example, Guy Toscano and William Weber, “Violence in the
workplace,” and Scott Richardson and Rene Reyes, “Fatal work injuries in
construction in Texas, 1991–93,” Compensation and Working Conditions,
April 1995, pp. 1–18; and Letitia K. Davis, et al, “Data sources for fatality
surveillance in commercial fishing: Massachusetts, 1987–91,” Compensation
and Working Conditions, July 1994, pp. 7–13

20

injuries to make CFOI counts as complete as possible. In
that regard, states have up to 8 months to update their initial
published counts with cases that were verified as workrelated after preliminary data collection has ended for a
given census. From 1992 to 2002, the updates have averaged
less than 1 percent of each year’s total that was initially
published. However, updates have been growing, and since
2003 average 2 percent of each year’s total that was initially
published. CFOI facilitates the exchange of information
by states on the fatal injuries that result from similar work
hazards, such as construction falls or workers being struck
by vehicles or equipment on or near roadways. Individual
states, moreover, can use CFOI data to provide information
to employers and their workers to promote safety in the
workplace. Users need to exercise caution in state-to-state
comparisons, however. For example, comparing rates for a
state with a large agricultural economy with that of a state
with a large industrial economy would be ill-advised because
agriculture has one of the highest fatal injury rates while
manufacturing has one of the lowest. In addition, the number
of fatalities and their circumstances can vary markedly
within a state from one year to the next, in part reflecting
single incidents involving multiple deaths, such as airplane
crashes and natural disasters.
In accordance with BLS policies, individually identifiable
data collected by CFOI are used exclusively for statistical
purposes and, under a pledge of confidentiality, are treated in
a manner that ensures no data published by CFOI identify a
particular decedent, fatal incident, or company.

with other governmental agencies, various “special topic”
surveys regarding occupational safety and health-related
topics. These special surveys have included the following
topics:
• Survey of Respirator Use and Practices
• Survey of Workplace Violence Prevention
The Survey of Respirator Use and Practices was a special
survey of U.S. employers regarding the use of respiratory
protective devices conducted by BLS for the National
Institute for Occupational Safety and Health (NIOSH),
Centers for Disease Control and Prevention. This voluntary
survey provided estimates of the number of establishments
and employees who used respirators during a 12-month
period by type of respirator and type of use. The survey
also collected data on the characteristics of the respirator
program at the establishment; assessment of medical fitness
to wear respirators; characteristics of respirator training at
the establishment; usefulness of NIOSH approval labels and
respirator manufacturers’ instructions; substances protected
against by the use of respirators, and fit testing methods used
for respirators. Results from this survey are available online
at http://www.bls.gov/iif/oshwc/osh/os/osnr0014.pdf.
The Survey of Workplace Violence Prevention was another
special survey conducted by BLS for NIOSH. This survey
studied the maintenance of a safe work environment, including
the prevalence of security features, risks facing employees,
employer policies and training, and related topics. Data from
this survey are available for private industry and state and
local government by industry and size of establishment,
where size is measured by the number of workers employed.
Results from this survey are available online at http://www.
bls.gov/iif/osh_wpvs.htm.

Part IV: Special Topic Surveys
In addition to the SOII and CFOI products normally produced
in any reference year, BLS has conducted, in conjunction

21

Technical References

Standard Occupational Classification Manual, 2000 edition.
Available online at http://www.bls.gov/soc/2000/soc_
majo.htm.

Abraham, Katharine G., William L. Weber, and Martin E.
Personick, “Improvements in the BLS Safety and Health
Statistical Program,” Monthly Labor Review, April 1996,
pp. 3–12. Available online at http://www.bls.gov/opub/
mlr/1996/04/art1full.pdf.

Standard Occupational Classification Manual, 2010 edition.
Available online at http://www.bls.gov/soc/home.htm.

Brown, Jeff. “Nonfatal injuries and illnesses in state and local
government workplaces in 2008,” Monthly Labor Review,
February 2011, pp. 33–40. Available online at http://www.
bls.gov/opub/mlr/2011/02/art3full.pdf.

Toscano, Guy A. and Janice Windau, “The Changing
Character of Fatal Work Injuries,” Monthly Labor Review,
October 1994, pp. 17–28. Available on the Internet at
http://www.bls.gov/opub/mlr/1994/10/art2full.pdf.

Compensation and Working Conditions (CWC) Online,
articles on safety and health topics, available online at
http://www.bls.gov/opub/cwc/osh.htm.

Toscano, Guy A. and Janice Windau, “Fatal Work Injuries
from the 1992 National Census,” Monthly Labor Review,
October 1993, pp. 39–48. Available online at http://www.
bls.gov/opub/mlr/1993/10/art3full.pdf.

Drudi, Dino, “A Century-long Quest for Meaningful and
Accurate Occupational Injury and Illness Statistics,”
Compensation and Working Conditions, Winter 1997, pp.
19–27. Available online at http://www.bls.gov/opub/cwc/
archive/winter1997art3.pdf.

Toscano, Guy A., Janice Windau, and Dino Drudi, “Using
the BLS Occupational Injury and Illness Classification
System as a Safety Management Tool,” Compensation
and Working Conditions, June 1996, pp. 19–28. Available
online at http://www.bls.gov/iif/oshwc/cfar0014.pdf.

Monthly Labor Review Online, articles on safety and health
topics, available online at http://www.bls.gov/opub/mlr/
indexa.htm.

U.S. Department of Labor, Report on the American Workforce,
chapter 3, “Safety and Health in the Workplace,” 1994.

North American Industry Classification System Manual, 2002
edition. Available online at http://www.census.gov/epcd/
naics02/index.html.

U.S. Department of Labor, OSHA Injury and Illness
Recordkeeping. Available online at http://www.osha.gov/
recordkeeping/index.html.

North American Industry Classification System Manual,
2007 edition. Available online at http://www.census.gov/
epcd/naics07/index.html.

Using Survey data to evaluate your firm’s injury and illness
experience. Guidelines to assist employers in comparing
their injury and illness experience to others with similar
size workforces in the same industry. Available online at
http://www.bls.gov/iif/osheval.htm.

Occupational Injury and Illness Classification System
(OIICS) Manual, version 2.0, September 2010. Detailed
BLS coding structures used to classify workplace injuries
resulting in death and for nonfatal injuries and illness
resulting in days away from work. Available online,
along with explanatory article, at http://www.bls.gov/iif/
oshoiics.htm.

William J. Wiatrowski. “Occupational safety and health
statistics: new data for a new century,” Monthly Labor
Review, October 2005, pp. 3–10. Available online at http://
www.bls.gov/opub/mlr/2005/10/art1full.pdf.
“Workplace injuries and illnesses,” “Nonfatal occupational
injuries and illnesses requiring days away from work,”
and “National census of fatal occupational injuries.” News
releases issued annually. Available for 1994 forward online
at http:/www.bls.gov/iif.

Occupational Injuries and Illnesses: Counts, Rates, and
Characteristics. Bulletins issued annually. (Prior to 1992,
Occupational Injuries and Illnesses in the United States by
Industry.)
Standard Industrial Classification Manual, 1987 edition.
Available online at http://www.osha.gov/pls/imis/sic_
manual.html.

22