CO Poisoning Guidelines

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OMB Control Number 3041-0029

INVESTIGATION GUIDELINE

Appendix 16
Revised October 2005
ALL CARBON MONOXIDE (CO) POISONING-RELATED INCIDENTS
(Including motor vehicles, generators, camping equipment and CO alarms 1 )

Table of Contents
Heading
I.

II.

Page

Introduction
A. Special Instructions
B. Background Information
C. Specific Items of Interest
D. Headquarters Contacts

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3
4
6

Instructions for Collecting General Information on the Incident
A. Free Text Summary
B. Description of the Incident Environment
Data Recording Sheet: General Information
C. Descriptio n of the Injured Person
Data Recording Sheet: Injured Persons
D. Description of Product
Data Recording Sheet: CO Alarms
E. Product Safety Standards

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6
8
11
13
15
17
20

III.

Instructions for Photographing and/or Diagramming Factors
Related to the Investigation

20

IV.

Instructions for Obtaining Samples and Documents
Related to the Investigation

22

V.

Instructions for Collecting Detailed Incident Information
in On-Site Investigations
Pre- On-Site Investigation CO Product Checklist
Data Recording Sheet: Residence Environment

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22
23

Up until October 1, 1998, “CO detector” was the accepted terminology. However, since that
date, both UL and IAS voluntary standards have replaced this terminology with “CO alarm” to
more accurately reflect the intended purpose of the product as an alarming device, rather than a
monitor.
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Table of Contents (cont’d)

I.

Heading

Page

Data Recording Sheet: Product Identification
Data Recording Sheet: Conditions of Vented Products
Gas Ranges/Ovens
Gas Water Heaters
Gas Central Furnaces
Space Heaters and Fireplace Log Sets
Wood Fireplaces, Woodburning Inserts, and Wood Stoves
Gas Clothes Dryers
Generators and Gas Engine Consumer Products
Gas Fired Portable Heaters

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27
29
31
34
38
41
44
46
48

INTRODUCTION

A. Special Instructions
A strategic goal of the Consumer Product Safety Commission is to reduce the rate of death from
carbon monoxide poisoning by 20% by the year 2013 (compared to the average of 1999 and
2000). To bolster this effort, CPSC staff is attempting to collect more detailed information on
CO poisoning and alarm incidents whe re possible, especially in on-site investigations. To gain
information about how interacting products and environmental effects impact CO incidents,
investigators are requested to collect a broad range of data when conducting on-site residence
investigations. Such detailed documentation is often required to support the case for voluntary
standards improvements or to prompt action from industry.
Investigators are requested to complete guideline sections I – III, including the data recording
sheets contained in these sections titled General Information, Injured Persons, and CO Alarms
(if applicable) for all CO-related investigations. In cases where limited information is
available (e.g., official documents only), please complete these sections with the amo unt of
information you have.
In addition to the above, when conducting an on-site investigation in a residence only,
investigators should complete guideline sections IV and V, including the data recording sheets
contained in these sections titled Residence Environment, Product Identification, and Conditions
of Vented Products. Section V of the guideline also contains data collection instructions and data
recording sheets corresponding to specific products that may be found in the residence. Only
complete these product-specific materials for each product that was in use during, or
immediately prior to, the CO incident. The Pre- On-site Investigation CO Product Checklist is
included so that investigators may identify these products before making the on-site visit.
The Pre- On-site Investigation CO Product Checklist may be used in the following way: While
making the appointment to conduct an on-site investigation, the investigator may use the
checklist to determine that a gas central furnace and a gas range were in use the day of the

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incident. In addition, the resident had used a woodburning fireplace (without an insert) early in
the day, and the residence had one CO alarm. The investigator would then conduct the on-site
interview, completing the guideline sections I – V, including the data recording sheets. In
section V, the product-specific instructions, and data recording sheets would be completed for
the gas central furnace, range, fireplace, and CO alarm. Assume the resident also owns a gas
clothes dryer, but it had not been in use around the time of the incident. The investigator would
not need to complete the guideline and data recording sheet for gas clothes dryers.
B. Background Information
Carbon monoxide (CO), in its pure state, is a colorless, odorless, and poisonous gas which results
from the combustion of organic materials such as gas, oil, wood, coal, and other domestic fuels.
The number of CO poisoning deaths associated with consumer products in non- fire situations in
the home ranged from 250 in 1991 to 180 in 1998. Mortality data indicate that gas heating
systems account for the majority of these deaths, primarily space heaters, both vented and ventfree, and furnaces. Portable camping heaters, lanterns, stoves or charcoal grills, as well as
gasoline-engine powered appliances and tools (e.g., pressure washers, generators, pumps), may
also result in CO poisoning.
CO poisoning in a home may result from the use of virtually any type of fuel-burning equipment
or a combination of equipment operating simultaneously under conditions where there is poor
ventilation or a potential for backdrafting. For example, picture an airtight house that has both a
gas furnace and a woodburning fireplace. The fireplace has been in use over a period of time
and it is giving off enough heat to keep the furnace thermostat above the threshold at which the
furnace would switch on. Because the house is air tight, the furnace vent acts as a path for air to
enter the house and, as a result, cold outdoor air has been back flowing through the vent,
replacing the air which the fireplace has been removing from the house. As the fire dies down or
the house gets colder, the thermostat switches the furnace on. Documented cases exist where the
furnace exhaust is unable to reverse the direction of the cold flue backdraft. As a result, the
furnace combustion products flow into the home, rather than out through the vent.2 The same
scenario could occur with the use of a dryer or attic fan instead of the fireplace.
Vehicle engine exhaust is another source of CO deaths, both intentional and unintentional.
Vehicles are not under CPSC jurisdiction; however, in such incidents where a vehicle was
running in an attached garage/carport and a CO alarm was in the home, an investigation should
be performed so that CPSC staff may develop a comprehensive evaluation of the preventionpotential of CO alarms. In the case of obvious suicide, CPSC staff is primarily interested in how
the CO alarms functioned and any overflow effects of CO on persons inside the home. CPSC
staff is also interested in CO incidents that occur in schools and other institutions, especially
when CO alarms were present. In the past, CPSC staff has worked on voluntary standards
relating to industrial- type appliances.

2

Stegmeir, Paul, Hearth and Home, February 1997, p. 39-4.
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Recent data shows that increasing cross-over of generators from occupational use to the
consumer market has resulted in an “epidemic” of generator-related CO deaths and injuries –
generators are now the fastest growing category of consumer products causing fatal CO
poisoning, and serious injuries. Generators are typically used by consumers when power is
unavailable due to weather-related conditions, termination of service for failure to pay bills, or
during construction activities. Generator-related CO deaths and injuries typically occur when
consumers operate generators inside living spaces, within enclosed spaces such as crawl spaces,
porches, garages and garden sheds, or outside of a home but with the generator exhaust in close
proximity to open windows, doors and/or air intake vents. The extremely high CO levels in
generator exhaust can rapidly infiltrate the entire home so that exposed occupants can lose
consciousness in less than an hour and will likely die without outside intervention.
Carbon monoxide alarms are devices that are designed to alert the occupants of a dwelling to
the presence of CO, at a stage early enough to prevent acute poisoning. They are usually
powered by battery or by household current (AC), or occasionally both. Some AC powered
alarms incorporate battery backup in case of electric power failure.
The three different technologies used in CO alarms are:
Biomimetic. The biomimetic technology utilizes a semi-permeable, initially clear gel that
darkens when exposed to CO. The gel absorbs CO at the same rate as the hemoglobin in the
blood, and its color change is directly related to the amount of CO it has absorbed. A beam of
light is passed through the gel, and the sensor determines any change (usually a reduction) in the
light intensity caused by color changes in the gel. When the color change corresponds to 10%
carboxyhemoglobin in the blood, the alarm sounds. The Biomimetic technology can be
distinguished in the field because the sensor and the battery are enclosed in a sensor pack. In
most models, this sensor pack must be replaced every two years; however certain alarms
utilizing Biomimetic technology are not subject to this requirement. Note that gel discoloration
can occur with aging and other exposure to non-CO chemicals.
Metal Oxide Sensor (MOS) or Taguchi. The metal oxide sensor technology uses a doped
semiconductor that changes conductivity when exposed to CO. An electronic circuit senses the
change in current through the semiconductor and sounds the alarm.
Electrochemical. The electrochemical sensor technology relies on an oxidation/reduction
reaction of CO with a reactive surface. The diffusion of CO gas into the sensor prompts the
chemical reaction, which in turn generates an electrical current through an external circuit,
sounding the alarm when potentially hazardous CO levels are reached.
C. Specific Items of Interest
CO from vehicles in an attached garage/carport, campground, or close to living spaces may result
in CO exposure to persons in the home, as well as to those near the source of CO.

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Provide the following data for cases involving vehicle exhaust: type of vehicle, manufacturer,
model (include year), location of vehicle, location of all victims, and information indicating
whether the incident was intent ional. Refer to the following product guidelines for technical and
background information if necessary:
- Appendix 91 (All-Terrain Vehicle)
- Appendix 70 (Snow Mobile).
· CO poisoning from portable camping lanterns, grills (gas and charcoal), heaters or stoves
often occurs in tents and vehicles such as campers or vans. For these cases, provide descriptive
information of the size of the area in which the product was used, any openings or ventilation to
the area, location of the victims and the position of the product. For vans, pick-up campers, RVs
and other vehicles, provide the manufacturer, model and year. For tents and other portable
structures, include the manufacturer, model, dimensions and materials of construction.
· For CO incidents involving an LP gas grill, provide the BTU rating and the length of time the
product had been operating up until the incident. Note if the fuel cylinder or appliance hoses or
fittings were cracked or separated. If a leak was detected, determine the exact location on the
appliance. Refer to the following product guideline for technical and background information if
necessary: Appendix 101 (Portable LP Gas Grills).
· For camping incidents, determine if heavy condensation was reported on the interior of the
enclosure. This is caused by the interior temperature exceeding the exterior ambient temperature
and may indicate inadequate ventilation.
· CO poisoning from small gasoline-engine powered appliances and tools have been known to
occur even in well- ventilated spaces partially exposed to the outdoors. For incidents involving
these products, provide the location of the product in relation to the victim at the time of the
incident. Describe and provide the dimensions of the area where the product was used. Describe
any openings or ventilation to the area, including fans and other venting devices, determine how
long the victim was in the room while the engine was running, and the victim’s workload prior to
the incident. Note if other occupants were involved and their position and status. If the engine
was operated outdoors, note the distance between the engine exhaust outlet and the air intake of
the room where the victim was working. Note if the engine was found in a switched on state and
whether the gas tank was empty or not when found. Refer to the following product guidelines
for technical and background information if necessary:
- Appendix 17 (Walk-behind Power Mower)
- Appendix 88 (Lawn Trimmer and Edger)
- Appendix 12 (Riding Mower)
- Appendix 14 (Log Splitter)
- Appendix 2 (Chain saw)
- Appendix 71 (Snow Thrower)
· Section V of this guideline (to be used for on-site residence investigations only) refers to
several products that may produce CO, as well as CO alarms. For many of these products,
however, other investigative guidelines exist which address hazards other than CO, such as fires

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or burns. Refer to the product guidelines as necessary to become familiar with the specific
background and technical aspects of the products, since they may not be covered in detail in this
CO guideline.
· Often it is difficult to determine the cause of CO poisoning. There may be conflicting
statements from the victim and other observers or investigators. Identify clearly the source of the
information you provide, i.e., the persons with whom you spoke or corresponded about the
incident. State clearly any conflicting opinions. If you have reason to believe that statements
made by any of the parties are inaccurate, please state why. Determine which federal, state or
local agency may be involved in the incident investigation and, if possible, obtain copies of any
written reports, and any photographs of the incident scene or products involved.
· If the manufacturer, model number, date of manufacture or installation date of an installed
appliance is not available, contact the local building or plumbing code or gas utility to determine
if a permit was issued for the appliance in question. Ask the first responder or other authoritative
investigating official to determine who the appropriate building or plumbing code official is. If a
permit was issued, request a copy of the permit. If a copy of the permit cannot be provided,
request the date of installation and manufacturer and model number if available.
· No guideline can cover all pertinent factors that may apply to a particular incident. Be sure to
include an explanation of any such factors in your narrative, even if CPSC staff has not
specifically mentioned them in these guidelines.
D. Headquarters Contacts
Donald Switzer, ESFS, 301 504-7534 and Janet Buyer, ESFS 301-504-7542
II.

INSTRUCTIONS FOR COLLECTING GENERAL INFORMATION ON THE
INCIDENT

A. Free Text Summary
Please provide a summary of the sequence of events that occurred prior to, during, and
subsequent to the incident. Be sure the words carbon monoxide are used in the synopsis.
B. Description of the Incident Environment
· Provide a comprehensive description of the residence, vehicle, tent, or other enclosure where
the incident occurred. For residences, include the number of levels, ceiling heights, materials of
construction, the age of the home, dimensions, and the approximate square footage. Note if
home had ductwork for HVAC system and if a system was in place. Also, determine any
materials used to reduce air exchanges from outside to inside (e.g., weather stripping, storm
windows, etc.). Also, for all cases, note if there were doors/windows and whether they were
open or closed.

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· Note if the residence had a woodburning fireplace and chimney, any type of fireplace insert, or
a gas fireplace. For each fireplace, include whether it was masonry or a factory-built type.
· Specify the incident location; e.g., apartment, private home, tent, cabin, RV, camper, van,
vehicle garage. Note the locations of all victims within that location. Note if the home or
enclosure had been recently renovated, painted, or newly furnished.
· Describe the ventilation conditions in the location where the incident occurred, as well as the
approximate temperature, both inside and out, at the time the victim(s) were found.
(Previous investigations have often mentioned an unusually hot temperature in the room where
the victims were found.)
· Report the temperature setting of the thermostat at the time of the incident and the approximate
size of the room(s) where the product(s) suspected of producing CO were located.
· Determine if the resident noticed any odors in home or at the suspected product(s) prior to or
during incident. Although CO itself is odorless, incomplete combustion may produce strong
odors such as “rotten eggs” or propane. Describe any odors and the locations where they were
detected.
· State whether the consumer, firefighters, utility company, etc mentioned “backdrafting” as a
factor.
· Determine from weather reports the prevailing weather conditions on the day of the incident,
such as the outdoor temperature range, wind speed and direction, barometric pressure, and
relative humidity.
· Describe whether there was mildew or soot in the house (e.g., windows, walls, and floors) or
other enclosure. The existence of soot may indicate the presence of incomplete combustion.
Soot on a vent- free fuel-burning product, however, may be normal, depending on the amount and
location of the sooting and the age and history of the product involved. The amount of sooting
considered “normal” might vary considerably among vent-free products. Sooting is not
considered normal on vented products.
· Determine the number of exhaust/ventilation fans that were present in the residence and their
respective locations. For each fan, indicate whether it was vented to the outdoors or if it
recirculated air back indoors. Determine which fans, if any, were operating at the time of the
incident.
· Provide any CO measurements taken and under what conditions; e.g., after house was aired,
after appliance was relit. Also provide the type of instrument that was used to take the
measurements, the lowest level of CO the meter can detect, whether the meter is/has been
calibrated on a regular basis, and what kind of training the field personnel have on using the
equipment.

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DATA RECORDING SHEET: GENERAL INFORMATION
Complete for all incidents involving carbon monoxide poisoning and/or an activated CO alarm
as instructed and attach to CPSC form 182, Epidemiolo gic Investigation Report. The purpose of
this data recording sheet is to capture general information, victim information, and CO alarm
information (if applicable) for all CO incidents. In addition, it is designed to capture detailed
information concerning home environment conditions and individual products for CO incidents
that are investigated on-site in a residence.
Instructions for all CO investigations:
Please complete the data recording sheets entitled General Information (pp.8-10), Injured
Persons (pp.13-14), and CO Alarms (if applicable, pp.17-19) for all incidents. In addition,
when conducting an on site investigation in a residence (as opposed to an RV, outdoor
enclosure, etc.), complete the sections entitled Residence Environment (p.23-25), Product
Identification (p.26), and Conditions of Vented Products (p.27-28). For these on-sites, also
complete the data-recording sheet in section V (p.22) of the guideline for those products in use
around the time of the incident. Each product from the Pre- On-Site Investigation CO Product
Checklist (p. 22) is listed on a separate page (or similar products are grouped together on one
page) for your convenience.
GENERAL INFORMATION
1. Task number_____________________
2. Incident date (MM/DD/YYYY)_________
3. Completion of this investigation is based on (check one):
___
Site visit to residence where incident occurred (may include written reports)
Complete guideline sections I – V, including data recording sheets (for relevant
products).
___
Telephone interview and/or written reports (e.g., fire report)
Complete guideline sections I – III, including data recording sheets contained in
those sections.
___
Written reports or newsclips only
Complete guideline sections I – III, including data recording sheets contained in
those sections.
___
Other, specify _________________________
Complete guideline sections I – III, including data recording sheets contained in
those sections.
4. Type of residence: Check one.
___ Detached house
___ Attached house (e.g., townhouse, duplex)
___ Apartment building or condominium
___ Other, specify ___________________________
___ Don’t know

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DATA RECORDING SHEET: GENERAL INFORMATION (continued)
5. What is the approximate age of the residence where the incident occurred?
___ 0 – 5 years
___ 5 – 10 years old
___ 11 – 20 years old
___ 21 – 30 years old
___ 31 years or older
___ Don’t know
6.

Did the consumer smell an unusual odor (e.g., burning smell, rotten eggs) in the home or
near a gas appliance prior to or during the incident?
___ Yes ___ No ___ Don’t know

7.

At the time of the incident what was the approximate outdoor temperature where the
incident occurred?
___ Less than 32 degrees Fahrenheit
___ 32 to 50 degrees Fahrenheit
___ 51 to 70 degrees F
___ 71 to 90 degrees F
___ Over 90 degrees F
___ Don’t know

8.

At the time of the incident, how windy was it where the incident occurred?
___ Calm, not windy
___ Slightly windy
___ Very windy
___ Don’t know

9.

At the time of the incident, what was the approximate outdoor relative humidity where
the incident occurred?
___ Low humidity, 50% or less
___ Slightly humid, 50-80%
___ Very humid, over 80%
___ Don’t know

10.

Was it foggy or rainy at the location of the residence at the time of the incident?
___ Yes ___ No ___ Don’t know

(continued next page)

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DATA RECORDING SHEET: GENERAL INFORMATION (continued)

11.

Had there been a hurricane/tropical storm or ice storm near the time of the incident?
____ Yes ____No ____Don’t know _________________Hurricane/storm name if known

12.

Was a vehicle’s engine running in a garage, carport or driveway attached to or adjacent
to the residence during the incident?
___ Yes ___ No ___ Don’t know

13.

Was there a fire in the fireplace at the time of, or just prior to, the incident?
___ Yes ___ No ___ Don’t know

14.

Was the CO incident related to the use of camping equipment (e.g. portable camping
lanterns, heaters, stoves, grills, and hibachis)?
___ Yes ___ No ___ Don’t know

15.

If incident was related to the use of camping equipment, mark the type of equipment.
Check all that apply:
___ Lantern
___ Heater
___ portable stove
___ grill or hibachi
___ Other, specify __________________________
___ Don’t know

16.

Did someone turn off appliances or other sources of CO post-incident?
___ Yes ___ No ___ Don’t know

17.

Did someone open windows or doors to air out the residence?
___ Yes ___ No ___ Don’t know

18.

If the consumer left the residence immediately, were outside doors and windows left
open?
___ Yes ___ No ___ Don’t know

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C. Description of the Injured Person
•

Please report the activity of the victim(s) at the time of the incident, and their location in
relation to the suspected product or vehicle.

•

Estimate the length of time the victim was exposed to the CO.

•

Specify the number of persons exposed to the CO, the number who died, the number of ill
who survived, and the number unaffected.

•

Report the age, sex, and long term prognosis for each of the victims (Note: severely poisoned
survivors can appear to recover initially after oxygen treatment, but 2-4 weeks after CO
exposure can experience delayed effects of CO poisoning. These effects on the central
nervous system, termed “delayed neurological sequelae (DNS)”, can range from loss of
memory/inability to concentrate to frank personality changes and Parkinson’s disease- like
muscular effects that can have drastic impact on ability to function normally. Staff is
interested in learning more about the health status of CO poisoning survivors of generatorrelated incidents in the weeks/months after the accident.)

•

Describe all reported symptoms, the length of time these symptoms had been experienced
prior to the incident, and the nature and length of time of any after-effects of the incident.

•

Determine how the CO poisoning was diagnosed, such as by a medical examiner or coroner,
by a physician in an emergency room or doctor’s office, or by the victim himself. Indicate
type of treatment provided (specify if hyperbaric oxygen (HBO) treatment was given y/n/?),
whether hospitalized, and duration of hospital stay.

•

Describe health status of victim(s) prior to the incident, such as if the y were pregnant, had a
heart or lung condition, or allergies at the time of the incident, as these factors may influence
one’s susceptibility to CO poisoning. Also indicate if any of the victims were under the
influence of alcohol, drugs, or other medication. If they smoked, determine frequency and
type of product used (e.g., pipe, cigar, and cigarette). Note any preexisting physical
infirmities of the victim(s) that might relate to the incident.

•

Specify whether the carboxyhemoglobin level in the blood of the victim(s) had been
measured by the coroner or doctor and the type of COHb test done (e.g., blood test,
breathalyzer, etc.). Provide the measurement, if available. Determine approximately how
much time had passed between the exposure to CO and the COHb measurement and find out
if oxygen was administered to the victim prior to the measurement.

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•

Determine the method of transportation used by the victim (e.g., ambulance, driven by
someone, drove self) to receive any medical attention. This may indicate the severity of the
victim’s symptoms and if in-transit treatment was received.

•

Indicate costs associated with any medical treatment related to CO poisoning.

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DATA RECORDING SHEET: INJURED PERSONS
1. How many non-firefighter victims were injured? Specify________
2. How many non-firefighter victims died? Specify_________
3. List the age, sex of each victim (up to 5 persons) and answer yes or no to whether the person
was injured or died.
Victim

Age (yrs)

Sex (M/F)

Died? Y/N

Died same day at
scene? Y/N

Injured? Y/N

Person 1
Person 2
Person 3
Person 4
Person 5

The next questions are about the most severely injured victims – please complete this section
for each severely poisoned victim who received hyperbaric oxygen treatment, or who was
admitted to hospital for more than 24 hours. If no victims meet these criteria, complete the
questions only for the most severely poisoned victim.
4. How long was the victim in the home prior to the incident?
___ Less than 30 minutes
___ 30 minutes to 1 hour
___ 1 – 2 hours
___ More than 2 hours
___ Don’t know
5. Was the victim a smoker?
___ Yes ___ No ___ Don’t know

If “no” or “don’t know” go to question 8.

6. If the victim smoked cigarettes, how many did he/she smoke a day?
Specify, if known ________
___ Don’t know
7. If the victim smoked cigars, how many did he/she smoke a day?
Specify, if known ________ ___ Don’t know
8. Did the victim receive medical treatment from a hospital emergency room as a result of the
incident?
___ Yes ___ No ___ Don’t know
(continued next page)

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DATA RECORDING SHEET: INJURED PERSONS (continued)
9. Did the victim have a blood test to measure exposure to CO poisoning?
___ Yes ___ No ___ Don’t know
10. If a blood test was given for CO poisoning, will the victim allow the CPSC investigator
access to the medical test result?
___ Yes ___ No ___ Don’t know

11. Did the victim receive hyperbaric oxygen therapy (HBO), and if so how many HBO
treatments were given?
___ Yes ___ No ___ Don’t know
12. At this time, does the victim/victim’s family consider the victim has fully recovered from the
CO exposure?
___ Yes ___ No ___ Don’t know (victim)
___ Yes ___ No ___ Don’t know (family member – specify relationship____________)
_____Note how many days have lapsed since the CO exposure occurred and this assessment
13. For any victim/family member who answered “no” to question 12, please note specifics of
effects/symptoms that are considered to still impact the victim and when they were first noticed.
14. Is victim still under medical care for health effects related to the CO poisoning incident?
___ Yes ___ No ___ Don’t know. If yes, provide further details.

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D. Description of Product
This information should be provided for the product(s) suspected as being responsible for excess
CO emissions and/or any CO alarms.
Suspected Product
•

Describe reported source of CO (e.g., rusted heat exchanger, clogged flue or vent,
disconnected or missing flue or vent, rusted flue or vent, failed vent damper, burning
charcoal, vehicle exhaust, etc.)

•

Report the manufacturer, brand name, model number, and serial number of the product.

•

Note the age of the product, whether purchased new or used, and if used, the length of time
the present owners have had the product. Note if the product had been borrowed or rented.
Note the user’s experience with using the product - had he/she ever used one before? Used
the one involved in the incident before?

•

Determine how frequently the product was used and generally, the length of time it was used.

•

Determine the length of time the product had been installed in its most recent location prior
to the incident. Also note who had installed it; e.g., professional, non-professional such as
homeowner, etc., and the kind of room in whic h it was installed, such as bedroom, living
room, etc.

•

Determine if the victim(s) had been aware of any instances of product malfunction prior to
the incident, such as the pilot light going out, the unit not heating properly, etc. If so,
describe the nature of the problem and if the user had done anything to the product in an
attempt to correct the malfunction. If they had the product serviced, please note how long
before the incident, and by whom, this was done. If appropriate, contact the repair person for
further information about the nature of repairs and obtain copies of any repair orders.

•

Describe in detail the product suspected in the incident. If necessary, please refer to other
guidelines for product-specific background and technical information. Include information
such as:
- Dimensions
- Type of fuel (if gas, LP or natural)
- Whether the product was portable (fuel contained within unit) or permanently
installed
- Whether the product was equipped with a thermostat, and if so, the setting at the time
of the incident
- For vented products, include whether the product had a vent damper installed in the
vent pipe, and if so, how long ago it was installed

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INVESTIGATION GUIDELINE

•
•

Provide the contents of any other labeling present on the product such as warning or
instructions for use or installation. Determine if the owner or user of the product involved
had possession or access to an owner’s manual for the product involved.
Determine if there was any ventilation of the product at the time of the incident, and if so,
describe (e.g., attached vent pipe, opening on side or top of product ). Describe whether the
venting system was reported to be properly constructed, installed, and/or maintained.

•

For portable camping equipment, determine if the fuel source had product-warning labels.

•

For incidents involving charcoal grills or hibachis, provide the contents of any warning labels
on the charcoal bag. Determine if the labeling is in compliance with the Federal Hazardous
Substances Act, Products Requiring Special Labeling, section 1500.14 (iii) (6). If possible,
determine the English language reading and speaking abilities of the victims and if they were
known to have read the warning labels.

•

If the product was a small gasoline-engine powered appliance or tool, determine if it was
owned by the consumer, borrowed, or rented for use. If product was rented, then obtain the
name and address of rental agency. Ask if the rental agency had warned the consumer of
possible CO hazards associated with the product verbally or in writing. Did/does the rental
agency have portable CO monitors or alarms available for rent as well?

CO Alarm(s) [if applicable]
•

For each alarm, report the type, manufacturer, brand name, model number, and date of
purchase/installation.

•

Give the location of alarm(s) in home.

•

Determine who responded to the emergency call (the fire department or the utility) and
whether CO measurements were taken. If possible, obtain any records of measurements
taken.

•

If the CO alarm sounded an alarm, did it stop on its own or continue to alarm? Did the
consumer disarm the alarm? Describe the consumer’s behavior before or after calling the
utility/fire department (such as turning off appliances, opening doors/windows, exiting
immediately).

•

Determine from the consumer or other reports if the consumer considered the CO alarm(s) to
be too sensitive. Also, indicate whether there was any history of the alarm sounding prior to
the incident.

•

If applicable, indicate the condition of the alarm’s biomimetic sensor (e.g., dark, light).

•

If a sample was collected, please include the sample collection number.

16

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: CO ALARMS
CO ALARMS: If no CO alarm present or don’t know, then skip.
1. How many carbon monoxide (CO) alarms are in the residence?
Specify:_______
___ Don’t kno w
2. Did any CO alarms in the residence activate at the time of the incident?
___ Yes ___ No ___ Don’t know
3. If a CO alarm activated, what room was the alarm located in? Check all that apply.
___ Kitchen
___ Bedroom
___ Basement
___ Other room: specify_________________________
___ Don’t know
4. Does the CO alarm have a digital display of CO levels (ppm)?
___ Yes ___ No ___ Don’t know
5. What type of warning signal does the alarm have?
___ Audible only
___ Visual only
___ Audible and visual
___ Don’t know
6. Can the consumer tell the difference among warning, full alarm, and fault signals?
___ Yes ___ No ___ Don’t know
7. If the CO alarm is a battery operated model with a replacement sensor, how many times was
the sensor replaced? Specify number _________________
8. Has the consumer ever ignored a CO alarm warning signal or full alarm?
___ Yes ___ No ___ Don’t know
9. Is the consumer satisfied with the CO alarm’s reliability?
___ Yes ___ No ___ Don’t know
10. If the consumer is not satisfied with the CO alarm’s reliability, did the consumer:
___ Continue to use the same CO alarm
___ Replace the CO alarm with the same or different model
___ Stop using the CO alarm
___ Don’t know

17

(continued next page)

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: CO ALARMS (continued)

11. When did the CO alarm sound?
Date_____ Time_____ ___ AM ___ PM ___ Don’t know
12. What happened after the CO alarmed?
___ It stopped
___ It continued alarming
___ It was turned off by someone
___ Don’t know
13. What fuel-burning appliances were operating at the time the CO alarm sounded?
___ Range or oven
___ Furnace
___ Water heater
___ Space heater
___ Fireplace (including logset or insert)
___ Clothes dryer
___ Other, specify_________
___ Don’t know
14. What fuel-burning appliances were operating 24 hours before the CO alarm sounded?
___ Range or oven
___ Furnace
___ Water heater
___ Space heater
___ Fireplace (including logset or insert)
___ Clothes dryer
___ Other, specify_________
___ Don’t know

15. Were the appliances operating normally?
___Yes ___ No ___ Don’t know
16. Did someone disarm the alarm?
___ Yes ___ No ___ Don’t know
17.Were there any prior incidents of the CO alarm sounding?
___ Yes ___ No ___ Don’t know

(continued next page)

18

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: CO ALARMS (continued)

18.What was the source or cause of the CO incident?
___ Range
___ Furnace
___ Water heater
___ Fireplace or logset
___ Clothes dryer
___ Other, specify_________________
___ Don’t know

19

INVESTIGATION GUIDELINE

E. Product Safety Standards
•

Determine if the suspected product had a certification label or any other indication that it was
safety tested, and if so, by whom; e.g., UL, IAS, AGA, etc.

•

If the product is a vent- free gas- fired heater, determine the presence of an oxygen depletion
sensor (ODS). Look for and note the presence of a safety label which indicates the presence
of an ODS.

•

If CO alarm(s) were present, note if they met any standard, e.g., UL, IAS.

III.

PHOTOGRAPH/DIAGRAMS OF INCIDENT SCENE

PHOTOGRAPHING
•

Photograph the product reported to be involved in the incident, being sure to include a clear,
and labeled view of any components which are defective or improperly installed or
maintained. Also photograph any labeling present on the product such as certification
emblems, warnings, or instructions for use or installation.

•

Photograph evidence of mildew, moisture, sooting inside structure of home (other than on
products).

•

For all fuel-burning products that were in use at the time of the incident, photograph the
visible portion of vent system, especially any conditions such as vent pipe
separations/sagging, holes or blockages, including any blockage of the vent damper. If no
vent pipe was attached, photograph any openings on the product.

•

Photograph conditions of soot, rust, or debris on product burners or heat exchangers. Also
photograph any blockages found. Photograph evidence of heat/fire damage to any of the
products, as well as any soot, rust or debris found inside a unit’s cabinet.

20

INVESTIGATION GUIDELINE

DIAGRAMMING THE LOCATION
Provide the approximate dimensions of the exterior of the house, dimensions of rooms with
fuel-burning products, dimensions of room(s) where the victim(s) was located, and the ceiling
height of each level of the house, including the basement. Show the locations of the following at
the time of the incident (see example sketch below):
- All fuel-burning products and vent pipes (if applicable)
- CO alarm(s)
- Doors, windows, or other openings that may normally provide some ventilation for the
residence
- Kitchen/room exhaust fans and attic fans
- Fireplaces/chimneys
- Fans or blowers associated with fireplace inserts, wood stoves, or gas log sets
- Supply and return air duct openings
- Room vent registers
- Running motor vehicle in an attached garage
- Include length of horizontal vents
NOTE: THE SKETCH IS ONLY AN EXAMPLE! THE SAME LEVEL OF NEATNESS
IS NOT REQUIRED!

21

INVESTIGATION GUIDELINE

IV.

OBTAINING SAMPLES AND DOCUMENTS RELATED TO THE
INVESTIGATION

· Obtain a copy of the fire department/and or utility reports and, if possible, a copy of the product
installation and maintenance instructions. If necessary, contact Compliance staff for subpoena.
Sample any alarm found which does not work for any reason other than missing, dead, or
incorrectly inserted batteries. But if batteries were removed to prevent nuisance alarms, collect
that alarm as a sample as well.
· For CO-related fatalities, collect all official documentation including coroners’ and medical
examiners’ reports and police reports. For CO-related hospitalizations, determine the type of
treatment administered and the duration of hospitalization.
V. INSTRUCTIONS FOR COLLECTING DETAILED INFORMATION ON
INDIVIDUAL PRODUCTS AND HOME CONDITIONS
This section of the guideline contains data recording sheets for the following topics: Residence
Environment, Product Identification, and Conditions of Vented Products. This section also
contains instructions and data recording sheets to be used in collecting detailed data on specific
fuel-burning products that may be involved in CO incidents. The Pre- On-Site Investigation CO
Product Checklist below lists these produc ts. CPSC Staff suggests that you determine which of
these products were in use around the time of the incident prior to conducting the on-site visit.
Given the amount of data requested in the on-site investigations, it may help to know ahead of
time the number and type of products for which materials will need to be completed.
PRE- ON-SITE INVESTIGATION CO PRODUCT CHECKLIST
____ RANGE/OVEN
____ GAS WATER HEATER
____ GAS CENTRAL FURNACE
____ GAS SPACE HEATER/GAS LOG SET
____ WOOD FIREPLACE/WOODBURNING INSERT/WOOD STOVE
____ GAS CLOTHES DRYER
____ GENERATORS AND OTHER ENGINE-POWERED CONSUMER PRODUCTS
____GAS FIRED PORTABLE HEATER
____ OTHER PRODUCT, Please specify _____________

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: RESIDENCE ENVIRONMENT
1. Around the time of the inc ident, did the consumer notice any mildew or moisture around
windows?
___ Yes ___ No ___ Don’t know
2. Around the time of the incident, did the consumer notice any sooting on walls, floors, or
other areas of the residence?
___ Yes ___ No ___ Don’t know
3. Was the consumer ever told by a firefighter, utility company employee, or any other
professional that they had a backdrafting problem?
___ Yes ___ No ___ Don’t know
4. How many exhaust fans are in the residence?
Specify:_______

___ Don’t know

5. How many exhaust fans were in use at time of, or immediately prior to, the incident?
Specify:_______

___ Don’t know

6. Location of exhaust fans: Check all that apply in the table below.
Exhaust Fan
Location

Is there an exhaust fan
located in this room?
Yes
No

Don’t
know

Is the exhaust fan vented to
the outside?
Yes
No
Don’t
know

Kitchen
Bathroom
Attic
Basement
Other room:
Specify____
____

(continued next page).

23

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: RESIDENCE ENVIRONMENT (continued)
7. Who was called first upon discovery of the incident?
___ Utility company
___ Fire department
___ No one was called
___ Other
___ Don’t know
If no one was called, then END of section.
8. What was the time of the call?
Specify:________ ___ AM ___ PM ___ Don’t know
9. Who responded first?
___ Utility company
___ Fire department
___ Other
___ Don’t know
10. What was the time of arrival?
Specify:________ ___ AM ___ PM ___ Don’t know
11. Were CO measurements taken?
___ Yes ___ No ___ Don’t know
If no CO measurements were done by anyone, then END of section.
12. What instrument was used to measure the CO?
Specify brand , if known________________ ___ Don’t know
13. What is the lowest CO level the meter can detect?
Specify in ppm _____________ ___ Don’t know
14. Is the meter calibrated or checked for calibration regularly?
___ Yes ___ No ___ Don’t know
(continued next page).

24

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: RESIDENCE ENVIRONMENT (continued)
15. When was the last time the meter was calibrated?
___ Less than 1 week before the first measurement was taken
___ 1 week to 1 month before the first measurement was taken
___ 1 month to 6 months before the first measurement was taken
___ More than 6 months before the first measurement was taken
___ Don’t know
16. Who took the measurements?
___ Utility company
___ Fire department
___ CPSC field investigator
___ Other
___ Don’t know
17. What training did this person have about using the CO meter?
___ Hands on training by someone else
___ Written instructions or video training
___ No training
___ Don’t know
18. Complete the following table for each CO measurement taken in the residence:
Fuel-burning
appliances in
use during
measurement

Date & time of
measurement

Location of
meas’ments
in the home

Number of
meas’ments
done

25

CO levels(in
ppm)

Duration of
measurements

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: PRODUCT IDENTIFICATION
Please mark (X) yes, no or don’t know for each product in the residence and in use at the time of,
or immediately prior to, the CO incident.
Product present in the residence?
Product

Yes

No

Don’t
know

Gas range or oven
Wood stove
LP gas grill
Gas water heater
Furnace
Natural Gas
LP Gas
Oil
Wood
Is furnace part of forced
air central Heating system?
Space heater
Electric
Gas
Kerosene
Fireplace
Gas / Masonry
Gas / Factory-built
Woodburning / Masonry
Woodburning / Factory-built
Fireplace Insert
Gas
Wood burning
Gas clothes Dryer
Generator
Other
Specify__________

26

Product in use during/prior to the
CO incident?
Yes
No
Don’t
know

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: CONDITIONS OF VENTED PRODUCTS
If no vented products were in use around the time of the incident, then skip.
For all vented products listed below that were in use at the time of, or immediately prior to, the
CO incident, mark each condition that existed at that time.
Is the product
vented?
Gas Fueled
Products

Yes

No

DK

If vente d, mark (X) each condition that existed.
Partial
Block

Complete
Block

Gap in
vent or
vent
separated

Vent
Holes

Size of
hole/gap
in vent
(inches)

Vent
Horizontal
only

Mark (X) if
horizontal
vent has
terminal or
wind cap
on outside
wall

Range/oven
Wood stove
Water heater
Furnace
Space heater
Fireplace/logsets
Clothes dryer
If vente d, mark (X) each condition that existed.

Gas Fueled
Products

Sagging
vent

Distance
from any
problem
in vent, to
appliance
(inches)

Metal
Vent

Vent both
Plastic horizontal
Vent
and
vertical

Range/oven
Wood stove
Water heater
Furnace
Space heater
Fireplace/logsets
Clothes dryer

(continued next page)

27

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: CONDITIONS OF VENTED PRODUCTS (continued)
If vente d, mark (X) each condition that existed.
Gas Fueled
Products

Vent,
Vertical
Only

Vented to 2nd
pipe

Vented to
Chimney

Range/oven
Wood stove
Water heater
Furnace
Space heater
Fireplace/logsets
Clothes dryer

28

Vent Damper
Installed

Distance from
vent damper
to appliance
(inches)

INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
RANGES/OVENS
Refer to Appendix 6 (Ranges and Ovens) for technical information.
•

Note the fuel type of the appliance and the BTU rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

List any observed or reported soot, rust, or debris on the appliance’s burner. Also list any
blockages in the burners, what caused the blockage, and note whether the blockage was
partial or complete.

•

List any observed or reported soot, rust, or debris inside the appliance’s cabinet/enclosure.

•

Note any observed or reported evidence of heat or fire damage, such as flame patterns,
charring, melted wires, discoloration, etc., anywhere on the appliance.

•

Determine if the consumer used aluminum foil or trays with the appliance, such as lining
burners or the bottom of the oven with these materials. Photograph any evidence of such
usage.

•

Note if the oven had a self-cleaning feature. If so, was this feature in use at the time of the
incident?

•

Indicate whether the range has an exhaust fan and describe how the exhaust is routed (i.e.,
vented outdoors or air recirculated into the kitchen).

•

If the range/oven had been used to heat the home, describe how this was done.

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS RANGE/OVENS
1. Was aluminum foil used on a top burner? ___ Yes ___ No ___ Don’t know
2. Was aluminum foil or an aluminum tray used to cover the bottom of the oven?
___ Yes ___ No ___ Don’t know
3. At the time of the incident, was the range or oven being used to heat the residence?
___ Yes ___ No ___ Don’t know
4. Is there soot, rust, or debris covering the burner?
___ Yes ___ No ___ Don’t know
5. What color is the burner flame?
___ Mostly yellow
___ Mostly blue
___ Don’t know
6. Is the burner flame of uniform height? ___ Yes ___ No ___ Don’t know.

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INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
GAS WATER HEATERS
Refer to Appendix 22 (Gas Water Heaters) for technical information.
•

Note the fuel type of the appliance and the BTU rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

Determine if a vent pipe was attached to the appliance or if it was missing. If missing, note if
he appliance had an opening at the top or side. Indicate if a vent damper was installed in any
vent pipe.

•

Describe the vent configuration, including the material (corrugated aluminum, plastic,
galvanized steel, etc.) and color of the vent. Note the condition of the vent, such as pipe
separations/sagging, holes or blockage. In addition, take the following measurements:
- Length and slope of vertical vent pipe or section
- Diameter of horizontal vent pipe or section
- Diameter of vertical vent pipe or section
- Distance from any of the above vent conditions to the point at which the vent pipe
attached to the appliance

•

List any observed or reported soot, rust, or debris on the appliance’s burner and heat
exchanger. List any blockages in the burners and heat exchanger. What caused the
blockage? Was there partial or complete blockage?

•

List any observed or reported soot, rust, or debris inside the appliance’s enclosure.

•

Note any observed or reported evidence of heat or fire damage, such as flame patterns,
charring, melted wires, discoloration, etc. anywhere on the appliance.

•

Note if the water heater was installed on a stand, and if so, provide the stand height.

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS WATER HEATERS
1. Is the water heater installed on a stand so the water heater sits above the floor?
___ Yes ___ No ___ Don’t know
2. If the water heater is installed on a stand, what is the approximate height of the stand?
Specify_________ inches. ___ Don’t know
3. Is there soot, rust, or debris covering the burner?
___ Yes ___ No ___ Don’t know
4. What color is the burner flame?
___ Mostly yellow
___ Mostly blue
___ Don’t know
5. Is the burner flame of uniform height? ___ Yes ___ No ___ Don’t know
6. Are there burn or flame patterns on the outside of the heater cabinet?
___ Yes ___ No ___ Don’t know
7. If the furnace and water heater are both vented into a common chimney or vent, which vent
pipe is higher? Check one.
___ Furnace vent pipe is higher
___ Water heater vent pipe is higher
___ Don’t know
8. If the furnace and water heater are vented into a common chimney or vent, what is the
distance between the two vents? Measure and specify. _________ inches
9. What color is the vent material? Check one.
___ White
___ Orange
___ Gray or silver
___ Other, specify __________
___ Don’t know
(continued next page)

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS WATER HEATERS (continued)
10. Where is the vent on the appliance?
___ Top
___ Side
___ Other, specify _________
___ Don’t know
11. Is there a vent damper in the vent pipe?
___ Yes ___ No ___ Don’t know
12. If there is a vent damper, how is it actuated? Check one.
___ Thermally
___ Electrically

33

INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
GAS CENTRAL FURNACES
Refer to Appendix 98 (Natural and Liquefied Petroleum Gas Furnaces) for technical
information.
•

Note the fuel type of the appliance and the BTU rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

Note whether the furnace was installed in a small, closed space (e.g., closet, alcove) or an
open space (e.g., garage, basement). If installed in an open space, list any other fuel-burning
appliances (incl. fireplace) that were operating in the same space at the time of the incident.
Also in this case, photograph the arrangement the appliances in the space.

•

Note whether any large holes or separations exist in the return air ducts of the space where
the furnace is located.

•

Determine if a vent pipe was attached to the appliance or if it was missing. If missing, note if
the appliance had an opening at the top or side. Indicate if a vent damper was installed in any
vent pipe.

•

Describe the vent configuration, including the material (corrugated aluminum, plastic,
galvanized steel, etc.) and color of the vent. Note the condition of the vent, such as pipe
separations/sagging, holes or blockage. In addition, take the following measurements:
- Length and slope of horizontal vent pipe or section
- Length of vertical vent pipe or section
- Diameter of horizontal vent pipe or section
- Diameter of vertical vent pipe or section
- Distance from any of the above vent conditions to the point at which the vent pipe
attached to the appliance

•

Document the complete vent system showing slope and duct size and any vent damper. Use
sketches and photographs.

•

List any observed or reported soot, rust, or debris on the appliance’s burner and heat
exchanger. List any blockages in the burners and heat exchanger. What caused the
blockage? Was there partial or complete blockage?

•

List any observed or reported soot, rust, or debris inside the appliance’s cabinet.
(continued next page)

34

INVESTIGATION GUIDELINE

•

Note any observed or reported evidence of heat or fire damage, such as flame patterns,
charring, melted wires, discoloration, etc. anywhere on the appliance.

•

Note the weather conditions on the day of the incident since weather can affect vent systems.
What was the minimum and maximum outdoor temperature? What was the snowfall or ice
accumulation on the house?

•

Note if the vent outlet is above or below the roof line, if the vent outlet is on the upwind or
downwind side of the house, and if the vent outlet was blocked during the incident. Look for
soot, corrosion, birds’ nests, or ice.

•

List all appliances that share the same vent. Are any of these appliances high efficiency
appliances?

•

Note if the furnace was converted from one fuel to another (e.g., oil to gas furnace).

•

Has there been a change in the fresh air supply? How was it changed?

•

Note if the combustion air supplied to the furnace is drawn from inside or outside the
residence.

•

Note condition of any opening or louvered vent that connects the furnace space to outdoor
air.

•

If the furnace is high efficiency or 90+ AFUE/efficiency, measure the distance between the
vent pipe exit and the combustion air inlet.

•

Were the front cover panels on the furnace during or immediately after the incident?

35

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS CENTRAL FURNACES
1. Is the furnace installed in a closed space such as a closet or alcove?
___ Yes ___ No ___ Don’t know
2. Is the furnace installed in an open space such as a garage or basement?
___ Yes ___ No ___ Don’t know
3. How many other gas appliances are installed in the same space as the furnace? Specify how
many________ (If none, enter zero) ___ Don’t know
4. Is the furnace a high efficiency furnace?
___ Yes ___ No ___ Don’t know
5. Were the front cover panels on the furnace at the time of the incident?
___ Yes ___ No ___ Don’t know
6. Were the furnace registers blocked or covered up during the incident?
___ Yes ___ No ___ Don’t know
7. Is there soot, rust, or debris covering the burner or heat exchanger?
___ Yes ___ No ___ Don’t know
8. What color is the burner flame?
___ Mostly yellow
___ Mostly blue
___ Don’t know
9. Is the burner flame of uniform height? ___ Yes ___ No ___ Don’t know
10. Are there burn or flame patterns on the outside of the heater cabinet?
___ Yes ___ No ___ Don’t know
(continued next page)

36

INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS CENTRAL FURNACES (continued)
11. If the furnace and water heater are both vented into a common chimney or vent, which vent
pipe is higher? Check one.
___ Furnace vent pipe is higher
___ Water heater vent pipe is higher
___ Don’t know
12. If the furnace and water heater are vented into a common chimney or vent, what is the
distance between the two vents? Measure and specify. _________ inches
13. What color is the vent material? Check one.
___ White
___ Orange
___ Gray or silver
___ other, specify __________
___ Don’t know
14. Where is the vent on the appliance?
___ Top
___ Side
___ other, specify _________
___ Don’t know
15. Is there a vent damper in the vent pipe?
___ Yes ___ No ___ Don’t know
16. If there is a vent damper, how is it actuated? Check one.
___ Thermally
___ Electrically.

37

INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
SPACE HEATERS AND GAS LOG SETS
Refer to Appendix 72 (Space Heaters) and Appendix 18 (Kerosene Heaters) for technical
information.
•

If the heater was a GAS-FIRED PORTABLE HEATER, than the section specific to
GAS-FIRED PORTABLE HEATERS (beginning on page 48) should be completed.

•

Note the fuel type of the appliance and the BTU rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

Is the appliance vented or vent- free? If appliance is vented, determine if a vent pipe was
attached to the appliance or if it was missing. If missing, note if the appliance had an
opening at the top or side.

•

If appliance is vented, indicate whether combustion air was drawn from indoors or outdoors.
Also, describe whether/how the vent was defective (broken or cracked?).

•

If the appliance is vent-free, indicate whether the room was ventilated in accordance with the
owner’s manual/instructions. Was a window open for fresh air?

•

State whether an oxygen depletion sensor (ODS) was on the appliance.

•

Describe whether the burners were defective (leaking, ruptured?).

•

List any observed or reported soot, rust, or debris on the appliance’s burners. List any
blockages in the burners. What caused the blockage? Was there partial or complete
blockage?

•

Was the appliance lit while the gas was on?

(continued next page)

38

INVESTIGATION GUIDELINE

Gas Log Sets Only
• Describe the placement of the logs and if the set was installed in a fireplace with a chimney
(insert), gas fireplace, or open space. If installed in a fireplace with a chimney, determine if
the flue damper was opened or closed at the time of the incident.
•

If installed in a fireplace, get the following measurements from the installer/builder or take
them:
- Height of fireplace/enclosure
- Width of fireplace/enclosure
- Depth of fireplace/enclosure
- Distance between log set and floor
- Distance between log set and rear wall
- Distance between log set and side walls

•

Determine who installed or originally arranged the logs in place. Had the logs been moved
prior to the incident? If so, by whom and for what reason (e.g., cleaning)? How often had
the gas log set been used since then? Record any maintenance performed.

•

Note the material of the logs and if sooting occurred.

• Note any options with the gas log set, such as remote control, capability to adjust
flame height, fan/blower, thermostat, or other options.

39

INVESTIGATION GUIDELINE

DATA RECORDING SHEET :SPACE HEATERS AND FIREPLACE GAS LOG SETS
1. At the time of the incident, were any windows cracked open in the same room as the space
heater or fireplace gas log set?
Yes ___ No ___ Don’t know ___
2. If there is a gas log set in the residence, where is it installed?: Check one.
___ Free-standing enclosure
___ Fireplace
___ Open space
___ Don’t know
3. If a gas log set was installed in a fireplace, was the fireplace damper opened or closed at the
time of the CO incident?: Check one.
___ Opened
___ Closed
___ Don’t kno w
4. What color is the burner flame?
___ Mostly yellow
___ Mostly blue
___ Don’t know
5. Is the burner flame of uniform height? ___ Yes ___ No ___ Don’t know
6. What color is the vent material? Check one.
___ White
___ Orange
___ Gray or silver
___ Other, specify __________
___ Don’t know
7. Where is the vent on the appliance?
___ Top
___ Side
___ Other, specify _________
___ Don’t know.

40

INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
WOOD FIREPLACES, WOODBURNING INSERTS, AND WOOD STOVES
Refer to Appendix 36 (Fireplaces – Factory Built), Appendix 37 (Fireplace Inserts) and
Appendix 24 (Wood Stoves) for technical information.
•

Note the type of wood or other solid fuel that was used in the appliance (cord wood,
processed wood, wood construction materials, pellets, coal, charcoal, etc.) and the BTU
rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

Determine if a vent pipe was attached to the appliance or if it was missing. If missing, note if
the appliance had an opening at the top or side. Indicate if a vent damper was installed in any
vent pipe.

•

Describe the vent configuration, including the material (corrugated aluminum, plastic,
galvanized steel, etc.) and color of the vent. Note the condition of the vent, such as pipe
separations/sagging, holes or blockage. In addition, take the following measurements:
- Length and slope of horizontal vent pipe or section
- Length of vertical vent pipe or section
- Diameter of horizontal vent pipe or section
- Diameter of vertical vent pipe or section
- Distance from any of the above vent conditions to the point at which the vent
pipe attached to the appliance

•

List any observed or reported soot, rust, or debris inside the appliance’s cabinet/enclosure.

•

Note any observed or reported evidence of heat or fire damage, such as flame patterns
charring, melted wires, discoloration, etc. anywhere on the appliance.

•

Determine whether the flue damper was open or closed at the time of the incident.

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: WOOD FIREPLACES, WOODBURNING INSERTS AND
WOOD STOVES
WOOD FIREPLACES AND WOODBURNING INSERTS
1. At the time of the incident was the fireplace damper opened or closed? Check one.
___ Damper was opened
___ Damper was closed
___ Don’t know

2. Is there soot, rust, or debris around the fireplace or insert?
___ Yes ___ No ___ Don’t know
3. What color is the vent material? Check one.
___ White
___ Orange
___ Gray or silver
___ Other, specify __________
___ Don’t know
4. Where is the vent on the appliance?
___ Top
___ Side
___ Other, specify _________
___ Don’t know

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: WOOD STOVES
1. Is there soot, rust, or debris around the wood stove?
___ Yes ___ No ___ Don’t know
2. What color is the vent material? Check one.
___ White
___ Orange
___ Gray or silver
___ Other, specify __________
___ Don’t know
3. Where is the vent on the appliance?
___ Top
___ Side
___ Other, specify _________
___ Don’t know
4. Is there a vent damper in the vent pipe?
___ Yes ___ No ___ Don’t know
5. If there is a vent damper, how is it actuated? Check one.
___ Thermally
___ Electrically

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INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
GAS CLOTHES DRYERS
Refer to Appendix 43 (Clothes Dryers) for technical information.
•

Note the fuel type of the appliance and the BTU rating.

•

If the appliance was on prior to or during the incident, how long had it been operating up
until the incident?

•

Determine if exhaust tubing was attached to the appliance, and if not, indicate if the
appliance had an opening at the top or side.

•

Describe the exhaust tubing configuration, including the material (corrugated aluminum,
plastic, galvanized steel, etc.) and color of the tubing. Note the condition of the tubing, such
as separations, holes, or blockage. In addition, take the following measurements:
- Diameter of exhaust tubing
- Distance from any of the above vent conditions to the point at which the tubing is
attached to the appliance

•

List any observed or reported soot, rust, or debris on the appliance’s burner and heat
exchanger. List any blockages in the burners and heat exchanger. What caused the
blockage? Was their partial or complete blockage?

•

List any observed or reported soot, rust, or debris inside the appliance’s cabinet.

•

Note any observed or reported evidence of heat or fire damage, such as flame patterns,
charring, melted wires, discoloration, etc. anywhere on the appliance.

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: GAS CLOTHES DRYERS
1. Is there soot, rust, or debris covering the burner?
___ Yes ___ No ___ Don’t know
2. What color is the burner flame?
___ Mostly yellow
___ Mostly blue
___ Don’t know
3. Is the burner flame of uniform height? ___ Yes ___ No ___ Don’t know
4. What color is the exhaust tubing material? Check one.
___ White
___ Orange
___ Gray or silver
___ Other, specify __________
___ Don’t know
5. Where on the appliance is the exhaust tubing connected?
___ Top
___ Side
___ Other, specify _________
___ Don’t know.

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INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON
GENERATORS AND ENGINE-POWERED CONSUMER PRODUCTS
•

As part of the product description, include the age of the product, manufacturer, horsepower
(HP) of engine, and kilowatt/hour of output (continuous/rated watts). Lists name and address
of outlet where and when the product was purchased or rented.

•

Remember to include the product description of any CO alarms, including age of the product
and manufacturer.

•

Specify the type of fuel used by the product and document the amount of fuel (e.g., in
gallons) used just prior to the incident. Note whether the generator was found in a “switched
on” state and whether there was any fuel still in the tank.

•

If the generator was used indoors (this includes the basement, crawlspace, attached carport or
garage, or shed), find out why the consumer chose to operate it there as opposed to outdoors.
If the generator was used outdoors, also ask why they used it outdoors. Were they aware of
the CO poisoning hazard?

•

What was the weather like at the time the generator was operated? Was it raining, snowing,
or otherwise precipitating or looking like it might? If generator was used outdoors, was it
protected from the weather in any way? If so, how?

•

Why was the generator needed, i.e. was the power turned off, was the location not provided
with electrical service at all, was there a temporary power outage, etc.? If there was a power
outage, what was the cause of the outage – a hurricane, ice storm, tornado, etc.? If hurricane,
what was the name of the hurricane? How long had the power been out when the incident
occurred?

•

How long had the generator been used prior to the incident? What time of the day was it
run?

•

What was the generator supplying power to, i.e. what appliances, tools, etc.? Were they
plugged directly into the generator? Was an extension cord used? Was the generator
connected to an electrical service panel? If so, please describe how it was connected.

•

Document the square footage and layout of room or partially enclosed area where victims
and generator (if used indoors) were located during the incident. Mark locations of any CO
alarms, fans, doors, and windows. Indicate whether fans were operating and which doors or
windows were open during the incident. Describe how far the doors and/or windows were
opened.

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INVESTIGATION GUIDELINE

•

Find out if product was operating near a central heating or cooling unit or other appliance
that circulates air throughout the home. If so, describe how close the generator was to it.

•

If incident occurred while product was operating outdoors, describe how exhaust reached the
victim(s). Were there any open doors, open windows, vents, or air intakes to the home near
where the generator was operating? If so, how close was the generator to any of these? If
there was an open window or door, describe how far it was opened. What were the wind
conditions?

•

Did the consumer have prior experience using a generator? If so, please describe i.e. how
many times prior to the incident did he/she use a generator, at what locations (home,
camping,etc.).

•

Photograph product, if possible, including standards markings and warnings. Also document
any standards markings and warnings, including the year of the standard.

•

Copy pages of the owner’s manual or instructions, especially those that relate to ventilation
requirements and safety warnings, if available from the consumer.

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INVESTIGATION GUIDELINE

INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION ON GASFIRED PORTABLE HEATERS
•

Determine if the heater was attached to a disposable 1-pound bottle of propane gas or if it
was connected to a bulk tank of propane gas (e.g., 20-pounds).

•

Indicate the position of the gas valve on the fuel source and on the heater (i.e., open/closed).

•

Determine the style of the heater (e.g., single burner radiant heater, multiple burner radiant
heater, combination radiant heater/cooker, radiant heater equipped with an oxygen depletion
sensor, or a catalytric heater).

•

If available, list the manufacturer, the model number, and the Btu/hr rating of the heater.
Note any damage or tampering to the product that may have occurred prior to the incident
that may have affected the performance of the heater.

•

List any other gas- fired equipment found at the scene and indicate if the gas valves on these
other equipment were open.

•

Photograph the gas-fired portable heater and attempt to collect the product as a sample with
this investigation. Note: it is generally not necessary to collect the fuel source in CO
poisioning incidents. If the product is not available to CPSC, document whether it was
retained by a third party for litigation, further examination, etc.

•

Sketch a layout of the area where the product and victims were located during the incident.
Mark locations of doors and windows and indicate if any of them were open during the
incident.

•

Describe the weather conditions present during the incident, including temperature range,
wind speed, etc.

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: Gas-Fired Portable Heater

7.75 in/
196.5 mm

3.875 in/
98.4 mm

1. What was the size of the propane tank that was connected to the heater?

____ 1 lb.

____ 4.25 lb. ____ 11 lb.

____ 14 lb.

____ 20 lb.

2. At the time of the incident, what was the position of the gas valve on the propane tank and on the
heater?
Propane Tank: ___ Open ___ Closed ___ Don’t know
Heater:

___ Open ___ Closed ___ Don’t know

3. Indicate which of the following heaters most closely resembles the heater involved in the incident.
a. Camping Heater (connects to a 1-pound propane bottle)

_______ Single Burner
Radiant Heater

_______ Combination
Heater/Cooker

Location of
ODS

______ Radiant Heater Equipped with
an Oxygen Depletion Sensor (ODS)

_______ Catalytic Heater

(continued on next page)

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INVESTIGATION GUIDELINE

DATA RECORDING SHEET: Gas-Fired Portable Heater (continued)
b. Tank-Top Heater (connects to a bulk propane tank)

_________

Single Burner
Heater

_________ Multiple Burner Radiant
Radiant Heater

4. Where did the incident occur?
____

Tent / Temporary Shelter

____

Camper / Trailer

____

Motor Vehicle (passenger vans, passenger cars, and cabs of semi trucks)

____

Other (specify): ____________________________________

5. What were the approximate dimensions of the space in which the incident occurred?
(L x W x H): _____________ x _____________ x _____________
6. If the incident occurred inside of a tent or any other temporary shelter, provide a sketch showing the
approximate shape of the structure along with any doors and window. Also indicate if any of the
doors and windows were open during the incident.

7. If the incident occurred inside a trailer or motor vehicle, indicate the make and model.
Make: ________________
Model: ________________

50