Evaluation of Chemical 

and Particle Exposures 

During Vehicle Fire 

Suppression Training

Kenneth W. Fent, PhD

Douglas E. Evans, PhD

James Couch, MS, CIH

Health Hazard Evaluation Report

HETA 2008-0241-3113

Miami Township Fire and Rescue

Yellow Springs, Ohio

July 2010

Department of Health and Human Services

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific 

facility evaluated and may not be universally applicable. Any recommendations made are not to be 

considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE 

reports are available at http://www.cdc.gov/niosh/hhe/
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2008-0241-3113 Page i

Appendix A

Report Abbreviations.......................................................................ii

Highlights of the NIOSH Health Hazard Evaluation............iv

Summary ............................................................................vi

Introduction..........................................................................1

Assessment.........................................................................3

Results.................................................................................9

Discussion .........................................................................16

Conclusions.......................................................................20

Recommendations.............................................................20

References ........................................................................21

Contents

Occupational Exposure Limits and Health Effects.............29

Sampling and Analytical Methods .....................................25

Literature Review...............................................................27

Acknowledgments

Appendix B

Appendix C

Appendix D Tables ................................................................................35

Figures...............................................................................39

Acknowledgments and Availability of Report.....................45

Appendix E
Page ii Health Hazard Evaluation Report 2008-0241--3113

μg/m3 Micrograms per cubic meter

μm Micrometers

μm/cm3 Micrometers per cubic centimeters

μm2

/cm3 Squared micrometers per cubic centimeters

ACGIH® American Conference of Governmental Industrial Hygienists

cc/min Cubic centimeters per minute

CFR Code of Federal Regulations

cm Centimeters

cm3 Cubic centimeters

CO Carbon monoxide

CO2 Carbon dioxide

DBA di-n-butylamine

EIC Ethyl isocyanate

EPA Environmental Protection Agency

ft/min Feet per minute

HDI Hexamethylene diisocyanate

IARC International Agency for Research on Cancer

ICA Isocyanic acid

IPDI Isophorone diisocyanate

MDC Minimum detectable concentration

MDI Methylenediphenyl diisocyanate

mg/m3 Milligrams per cubic meter

MIC Methyl isocyanate

mm Millimeters

mph Miles per hour

MQC Minimum quantifiable concentration

N/A Not applicable

ND Non-detectable

NIOSH National Institute for Occupational Safety and Health

nm Nanometers

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PAH Polycyclic aromatic hydrocarbons

PBZ Personal breathing zone

PEL Permissible exposure limit

Abbreviations
Health Hazard Evaluation Report 2008-0241-3113 Page iii

Abbreviations

(continued)

PHI Phenyl isocyanate

PIC Propyl isocyanate

PPE Personal protective equipment

ppm Parts per million

REL Recommended exposure limit

SCBA Self-contained breathing apparatus

STEL Short term exposure limit

TD Thermal desorption

TDI Toluene diisocyanate

TLV® Threshold limit value

TRIG Total reactive isocyanate groups

TWA Time-weighted average

USC United States Code

VOC Volatile organic compound

WEEL Workplace environmental exposure level

XAD-2 Polystyrene/divinyl benzene based polymer
Page iv Health Hazard Evaluation Report 2008-0241--3113

Highlights of the

NIOSH Health

Hazard Evaluation

The National Institute for 

Occupational Safety and 

Health (NIOSH) received 

a request for a health 

hazard evaluation (HHE) 

from the Miami Township 

Fire and Rescue in Yellow 

Springs, Ohio. The request 

concerned chemical and 

particle exposures during 

vehicle fire suppression 

training.

What NIOSH Did on the First Evaluation

● We sampled the smoke from the engine and cabin fires from 

one vehicle on September 25, 2008. These samples were 

collected to identify the main chemicals in the smoke.

● We took personal breathing zone (PBZ) air samples on fire 

fighters. The samples were collected to look for volatile 

organic compounds, specific aromatic hydrocarbons, and 

acrylonitrile.

What NIOSH Found on the First Evaluation 

● We found high levels of hazardous chemicals in the vehicle 

fire smoke. However, the PBZ air concentrations were below 

occupational exposure limits (OELs).

What NIOSH Did on the Second Evaluation

● We used the results of the first evaluation to tell us what to 

sample for in the second evaluation.

● We took PBZ air samples on fire fighters during the engine 

and cabin fires from three vehicles on July 14, 2009. 

The samples were collected to look for specific aromatic 

hydrocarbons, aldeyhydes, isocyanates, and carbon monoxide 

(CO).

● We sampled near the vehicle fires for the same chemicals, 

except CO.

● We sampled the particles produced during the fires to 

characterize their size and concentration.

What NIOSH Found on the Second Evaluation

● Most of the PBZ air concentrations were below OELs.

● Two of 15 PBZ concentrations of formaldehyde were above 

the NIOSH ceiling limit. If the fire fighters had not worn 

SCBAs some of them would have been overexposed to 

formaldehyde, a carcinogen and respiratory sensitizer.

● One CO concentration was just below its OEL. So, 

overexposures to CO could occur. CO can deprive the body 

of oxygen.

● Some isocyanate concentrations were just below the OEL 

during cabin fires. One sample collected near the vehicle 

fires measured isocyanates above the OEL. So, overexposures 

to isocyanates could occur during cabin fire suppression. 

Isocyanates are respiratory sensitizers.
Health Hazard Evaluation Report 2008-0241-3113 Page v

Highlights of the

NIOSH Health

Hazard Evaluation

(continued)

● A large amount of small particles were generated during 

the fires. Small particles may be more harmful than large 

particles because they can go deeper into the lungs.

What Fire Chiefs Can Do

● Continue to enforce use of SCBAs during vehicle fire 

suppression. Include this practice in written policy.

● Attack fires from upwind positions; this will further reduce 

fire fighters’ exposures.

● Park the motor pump apparatus upwind of the fire. Doing 

so will lower exposures to the motor pump operator, who 

usually does not wear an SCBA.

What Fire Fighters Can Do

● Put on your SCBA before attacking a vehicle fire. Keep the 

SCBA on until overhaul is complete.

● Stay upwind of diesel exhaust sources such as exhaust pipes. 

Diesel exhaust contains harmful substances.

● Talk to the fire chief about any health and safety concerns.
Page vi Health Hazard Evaluation Report 2008-0241--3113

Summary

NIOSH evaluated fire 

fighter exposures to 

chemicals and particles 

during vehicle fire 

suppression training. 

We found many different 

chemicals and high 

particle concentrations 

during the fires. According 

to our measurements, 

the potential exists 

for overexposure to 

formaldehyde, isocyanates, 

and CO. We recommend 

that fire fighters wear 

SCBAs until overhaul 

is completed. We also 

recommend that fire 

fighters stand away from 

diesel exhaust and park 

fire apparatus upwind of 

the fires.

In July 2008, NIOSH received a health hazard evaluation request 

from management at the Miami Township Fire and Rescue in 

Yellow Springs, Ohio. The request concerned potential inhalation 

exposures during vehicle fire suppression training. We conducted 

our first evaluation on September 25, 2008, to identify the 

main chemical constituents of engine and cabin fires during a 

training exercise involving one vehicle (two sampling events). We 

found high levels of various hazardous chemicals that helped us 

determine what to sample for on the second evaluation. During 

our second evaluation on July 14, 2009, we measured fire fighters’ 

personal exposures to chemicals and particles during the engine 

and cabin fires for three vehicles (six sampling events). We 

conducted PBZ air sampling for aromatic hydrocarbons, aldehydes, 

CO, and isocyanates. In addition, we sampled for particles and 

other compounds near the fire fighters suppressing fires.

In both evaluations, most of the PBZ concentrations we measured 

were below STELs. However, 2 of 15 PBZ concentrations of 

formaldehyde exceeded the NIOSH ceiling limit of 0.12 mg/m3

. 

Although all the PBZ concentrations of isocyanates were below the 

STEL of 44 μg/m3, using statistics, we calculated a 27% probability 

of overexposure to isocyanates during cabin fire suppression. Most 

real-time CO measurements were below the NIOSH ceiling limit 

of 200 ppm; however, one measurement (196 ppm) taken in the 

PBZ of the fire fighter performing backup was just below this 

ceiling limit. We measured increased particle number and mass 

concentrations during the vehicle fire knockdown, which persisted 

through the overhaul phase of the fire response.

Our findings indicate a potential for acute overexposure to 

formaldehyde, CO, and isocyanates during vehicle fire suppression. 

A potential for fine particle exposure can occur at any point during 

fire suppression operations. The intensity and duration of both the 

chemical and particle exposures depends on the wind speed and 

direction. Therefore, we recommend that fire fighters wear SCBAs 

until completing overhaul. We also recommend that fire fighters 

stand away from any diesel exhaust and park fire apparatus upwind 

of the fires. In addition, the motor pump operator should remain 

upwind of the diesel exhaust emissions from the fire apparatus 

because they could contain harmful substances.

Keywords: NAICS 922160 (Fire Protection), fire suppression, 

vehicle fire, car fire, fire fighter exposures, particles, isocyanates, 

formaldehyde
Health Hazard Evaluation Report 2008-0241-3113 Page 1

Introduction

On July 22, 2008, NIOSH received a health hazard evaluation 

request from the Miami Township Fire and Rescue in Yellow 

Springs, Ohio. The request concerned potential inhalation 

exposures during vehicle fire suppression training. In response to 

this request, we conducted evaluations on September 25, 2008, 

and July 14, 2009.

The Miami Township Fire and Rescue conducts vehicle fire 

suppression training two to three times per year. Fewer than 4% 

of its fire responses (~400 total runs per year) are to vehicle fires, 

which is below the national rate of 20% [Ahrens 2004]. Salvaged 

vehicles are used in the training exercises, which take place in 

abandoned parking lots. Vehicle fire suppression training has three 

phases: (1) startup—when the fire is ignited and allowed to build, 

(2) knockdown—when the fire is suppressed with water, and (3) 

overhaul—when the fire fighters search for and suppress residual 

flames or flare-ups. Figures 1–3 provide photographs from these 

phases. During both evaluations, vehicle engines and cabins were 

separately set on fire with flares and accelerated with gasoline. 

The fire fighters waited 2–5 minutes to let the fires build before 

knockdown with water. Knockdown took 1–3 minutes and was 

followed by 1–4 minutes of overhaul.

The fire fighters wore full turnout gear and SCBAs the entire time 

they fought the fires, including during overhaul. Miami Township 

Fire and Rescue has a comprehensive written respiratory protection 

program that adheres to the OSHA Respiratory Protection 

Standard [29 CFR 1910.134] requiring annual medical clearance; 

respirator fit testing; and training on the use, maintenance, and 

care of SCBAs.

On the first evaluation, the engine and cabin of a 1991 Dodge 

Dynasty sedan were set on fire. Most of the belts and the battery 

were missing, and the gas tank had been emptied; the cabin 

interior was relatively unaltered. On the second evaluation, the 

engines and cabins were set on fire for three vehicles: a 1994 Ford 

Aerostar minivan, a 1986 Toyota Corolla sedan, and a 1986 Toyota 

Celica coupe. The belts, fluids, batteries, cushions, and upholstery 

were present in each vehicle, but the gas tanks had been emptied.
Page 2 Health Hazard Evaluation Report 2008-0241--3113

Introduction 

(continued)

Figure 3. Overhaul phase of vehicle fire suppression training.

Figure 2. Knockdown phase of vehicle fire suppression training.

Figure 1. Startup phase of vehicle fire suppression training.
Health Hazard Evaluation Report 2008-0241-3113 Page 3

Assessment

First Evaluation

Four fire fighters were involved in the suppression of the engine 

and cabin fires: a nozzle operator, a backup, a forcible entry, and 

an officer. The nozzle operator aimed the stream of water, backup 

assisted with holding the hose, forcible entry pried open doors or 

the hood to gain better access to the fires, and the officer managed 

the other fire fighters and assisted where needed.

We conducted PBZ air sampling and collected general area air 

samples of the smoke to identify chemicals emitted in the vehicle 

fires. A fire fighter in turnout gear and SCBA collected samples 

of the smoke from the engine and cabin fires. These samples were 

collected with 1-liter Summa canisters. The fire fighter collected 

the samples by holding the canisters in the smoke plume and 

opening the valve, which allowed the canister under vacuum to 

draw in 1 liter of the smoke (Figure 4). Six samples were collected 

in conjunction with startup, knockdown, and overhaul for each 

fire. Each sample of smoke was analyzed for VOCs. In addition, 

the four fire fighters suppressing the fires wore sampling trains 

containing TD tubes and charcoal tubes. The TD tubes identified 

the VOCs in the fire fighters’ PBZs, while the charcoal tubes 

quantified the PBZ concentrations of the following aromatic 

hydrocarbons: benzene, toluene, styrene, and naphthalene. 

Charcoal tubes were also used to quantify acrylonitrile. We 

changed the sampling media between the engine and cabin fires. 

In addition, VOC samples (TD tubes and Summa canisters) 

were collected before any fires had been set to characterize the 

background levels of contaminants. More details on the sampling 

and analytical methods used during the first evaluation are 

provided in Appendix A.

Figure 4. Fire fighter using Summa canisters to sample VOCs from a 

vehicle fire.
Page 4 Health Hazard Evaluation Report 2008-0241--3113

Assessment (continued) Second Evaluation 

Five fire fighters were involved in suppressing the vehicle fires or 

assisting with sampling: a nozzle operator, a backup, an officer, a 

motor pump operator, and a duct holder (for particle sampling). 

The officer or backup performed forcible entry during this 

evaluation. Different fire fighters were involved with each vehicle 

burn; however, the same fire fighter operated the motor pump for 

all fires.

We conducted PBZ and general area air sampling for specific 

chemical compounds. Based on the results of the first evaluation, 

as well as an extensive literature review (see Appendix B for a 

summary of the literature review), we decided to sample for 

specific aromatic hydrocarbons, aldehydes, isocyanates, and 

CO. Aromatic hydrocarbons, aldehydes, and CO are common 

byproducts of organic material combustion. Isocyanates are used 

in the manufacture of polyurethane materials, and we speculated 

they may be released when combusting polyurethane foam used in 

automobile seat cushions.

Each of the five fire fighters wore three sampling trains. The 

sampling trains contained charcoal tubes, XAD-2 tubes, or 

denuders (Figure 5). Only the denuders were changed between the 

engine and cabin fires (except for the denuder worn by the motor 

pump operator, which was changed between each vehicle burned). 

The charcoal tubes were used to measure PBZ concentrations of 

the following aromatic hydrocarbons: benzene, ethyl benzene, 

naphthalene, styrene, toluene, and xylenes. The XAD-2 tubes were 

used to measure PBZ concentrations of the following aldehydes: 

formaldehyde and acrolein. The denuders were used to measure 

PBZ concentrations of the following isocyanates: TDI, MDI, HDI, 

PHI, MIC, EIC, PIC, IPDI, and ICA. The fire fighters also wore 

real-time monitors (GasAlert Extreme, BW Technologies Ltd., 

Calgary, Canada) to measure their PBZ concentrations of CO over 

time. More details on the sampling and analytical methods used 

during the second evaluation are provided in Appendix A.

General area air samples were set up around each vehicle to 

measure the same chemicals as for the PBZ sampling (except CO). 

The area air samples were approximately 25 feet west, south, and 

east of the vehicles. No area air samples were set up to the north 

because of a field with tall grasses. None of the area air samples 

Figure 5. NIOSH investigator 

attaching a sampling pump to a 

fire fighter.
Health Hazard Evaluation Report 2008-0241-3113 Page 5

Assessment (continued) was changed between the engine and cabin fires. Table 1 provides 

an overview of the sampling scheme for the first and second 

evaluations, and Figure 6 provides a schematic of the second 

evaluation.

Table 1. Types and numbers of air samples collected during the first and second evaluations

Sampling media Analytes Method

Personal air 

sampling Area air 

sampling 

(n)†

Smoke 

plume 

sampling 

(n) N* n † †

First evaluation 

Charcoal tubes‡

Acrylonitrile, benzene, 

naphthalene, styrene, 

and toluene

NIOSH 1501¶ 4 8 N/A N/A

TD tubes‡ Numerous VOCs 

(qualitative) NIOSH 2549¶ 4 8 N/A N/A

Summa canister 75 VOCs (quantitative) EPA TO-15** N/A N/A N/A 6

Second evaluation 

Charcoal tubes

Benzene, ethyl 

benzene, naphthalene, 

styrene, toluene, and 

xylenes

NIOSH 1501¶ 15 15 9 N/A

XAD-2 tubes Formaldehyde and 

acrolein NIOSH 2541¶ 15 15 9 N/A

Denuders§

TDI, MDI, HDI, PHI, 

MIC, EIC, PIC, IPDI, 

ICA

[Marand et al. 

2005] 15 27 9 N/A

* N = number of fire fighters sampled.

†

 n = number of samples collected. This number does not include blanks or background samples.

‡

 TD tubes and charcoal tubes (personal sampling) were changed between the engine and cabin fires during 

the first evaluation.

§

 Denuders were changed between the engine and cabin fires during the second evaluation for all fire fighters 

except the motor pump operator.

¶

 NIOSH Manual of Analytical Methods [NIOSH 2010]

** EPA Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air [EPA 1999]
Page 6 Health Hazard Evaluation Report 2008-0241--3113

Assessment (continued)

Particles were sampled near fire fighters using 25 feet of flexible 

aluminum duct [Evans et al. 2010]. A blower unit downstream 

of the sampling platform drew smoke through the flexible duct. 

Multiple instruments then simultaneously and continuously 

monitored particles in the captured smoke. Particle metrics 

included number, active surface area, respirable mass, photoelectric 

response, and particle size distributions. A photograph of the 

particle sampling platform is provided in Figure 7. Appendix A 

provides more information on the particle sampling instruments 

and methodology.

In addition to chemical and particle sampling, we used a 

weather station to monitor weather conditions during the 

second evaluation (HOBO®, Onset Computer Corp., Bourne, 

Massachusetts). Air temperature, relative humidity, wind speed, 

and wind direction were recorded every minute. We also set up 

a thermal imaging camera (IR FlexCam Ti55, Fluke®, Everett, 

Washington) to capture images of the vehicle fires every 15 seconds 

to estimate the temperatures of the different phases of the fires. 

Finally, we recorded fire fighter activities with a digital camcorder 

(HDC-SD9P/PC, Panasonic®, Secaucus, New Jersey).

Figure 7. Photograph of the particle 

sampling platform housing multiple 

direct reading instruments.

Figure 6. Schematic of the second evaluation showing the location of the vehicle fires 

relative to the fire fighters, fire apparatus, and area samples.
Health Hazard Evaluation Report 2008-0241-3113 Page 7

Assessment (continued) Because vehicle fires are generally suppressed quickly (< 15 

minutes), STELs and ceiling limits are most appropriate for 

comparing the results of the personal air sampling rather than 

OELs that are usually based on 8-hour TWA exposures. Unless 

otherwise noted in this report, a STEL is a 15-minute TWA 

exposure that should not be exceeded at any time during a 

workday, and the ceiling limit is an exposure that should not be 

exceeded at any time. The NIOSH ceiling limit for CO is 200 

ppm [NIOSH 2005]. The NIOSH and OSHA ceiling limits for 

acrylonitrile are 22 mg/m3

 [NIOSH 2005]. The STELs and ceiling 

limits for the other chemicals we sampled are provided in Tables 

2 and 3. Currently, no STELs or ceiling limits exist for PHI, MIC, 

EIC, PIC, or particles. More information on OELs is provided in 

Appendix C.

Table 2. STELs and ceiling limits* (mg/m3) for the aromatic hydrocarbons and aldehydes that were sampled 

during the second evaluation

Benzene Ethyl 

benzene Naphthalene Styrene Toluene Xylenes Formaldehyde Acrolein

NIOSH 

REL† 3.2 545 80 425 565 650 C 0.12 0.80

OSHA 

PEL† 16 N/A N/A C 850 C 1130 N/A 2.45 N/A

ACGIH 

TLV‡ 8.0 545 80 170 N/A 650 C 0.37 C 0.23

* Ceiling limits denoted with the letter C.

†

 [NIOSH 2005]

‡

 [ACGIH 2009]
Page 8 Health Hazard Evaluation Report 2008-0241--3113

Assessment (continued)

Table 3. STELs and ceiling limits* (μg/m3) for the isocyanates that were sampled during the second evaluation

TDI MDI HDI IPDI TRIG

NIOSH REL† N/A C 67 C 70 C 68 N/A

OSHA PEL† C 68 C 67 N/A N/A N/A

ACGIH TLV‡ 68 N/A N/A N/A N/A

UK-HSE OEL§ N/A N/A N/A N/A 70

Sweden OEL¶ N/A N/A N/A N/A 44

* Ceiling limits denoted with the letter C.

†

 [NIOSH 2005]

‡

 [ACGIH 2009]

§

 [HSE 1999]

¶

 [Swedish National Board of Occupational Safety and Health 2000]
Health Hazard Evaluation Report 2008-0241-3113 Page 9

First Evaluation 

The primary purpose of the first evaluation was to identify the 

main constituents in the vehicle fire smoke. Table 4 presents the 

concentrations of 10 VOCs for each phase of the engine and 

cabin fire suppressions as measured with Summa canisters. The 

compounds reported in Table 4 were selected based on their 

relative abundance in the sampled smoke and on potential toxicity. 

For an ordered list of the 15 most abundant VOCs and their 

respective concentrations for each phase of the engine and cabin 

fire suppression, see Tables D1 and D2 in Appendix D.

Results

Table 4. Concentrations (mg/m3) of 10 selected volatile organic compounds in the vehicle fire smoke measured 

during the first evaluation

Select compounds

Engine fire Cabin fire

Start up Knockdown Overhaul Start up Knockdown Overhaul

Benzene 5.2 1.6 11 60 1.4 0.38

1,3-Butadiene 2.3 0.40 4.8 6.8 0.25 0.05

Toluene 1.4 9.3 3.8 10 4.6 0.95

Naphthalene 1.4 0.93 1.2 10 0.60 0.17

Styrene 0.83 3.3 1.6 14 2.3 0.45

Acrolein 0.56 0.35 1.4 15 0.18 0.05

Methyl methacrylate 0.44 0.17 0.21 0.33 0.81 0.06

Acrylonitrile 0.32 0 0.77 27 0.38 0.07

Acetonitrile 0.28 0.12 0.70 14 0.12 0.03

Ethyl benzene 0.15 2.2 0.41 1.4 0.7 0.12
Page 10 Health Hazard Evaluation Report 2008-0241--3113

Results (continued) We identified the highest peaks in the gas chromatograms for the 

most concentrated VOC samples collected with TD tubes during 

the engine and cabin fire suppressions. Aliphatic hydrocarbons 

(pentane, chlorodecane, and various C6 aliphatic hydrocarbons) 

and aromatic hydrocarbons (benzene, toluene, styrene, 

naphthalene, and xylenes) were elevated (compared to background 

samples) in the PBZs of the fire fighters during the suppression of 

the engine and cabin fires.

We also conducted PBZ air sampling for specific aromatic 

hydrocarbons during the first evaluation. Personal exposures 

are affected by wind speed and direction. The fire fighters at the 

Miami Township Fire and Rescue typically attack vehicle fires 

from an upwind position to minimize exposures and maximize 

visual perception. In this exercise, the fire fighters attacked the 

fires predominantly from the southeast direction. According to the 

National Weather Service [http://www.nws.noaa.gov], during this 

exercise, the wind was from the southwest (away from fire fighters 

attacking the fires) and averaged 14 mph, the temperature was 

80°F, and the relative humidity was 30%. 

Table 5 provides the PBZ concentrations of benzene and toluene 

measured during the cabin fire suppression. The MDCs and 

MQCs were calculated by dividing the respective analytical limits of 

detection and quantitation (mass units) by the minimum volume 

of air sampled. The MDCs and MQCs represent the smallest 

air concentrations that could have been detected (MDC) or 

quantified (MQC) based on the volume of air sampled. The PBZ 

concentrations of acrylonitrile, naphthalene, and styrene during 

the cabin fire suppression were ND (below their respective MDCs 

of 0.46, 2.3, and 0.11 mg/m3

). The MDC for benzene was 0.09 

mg/m3

; for toluene it was 0.11 mg/m3. All PBZ concentrations 

measured during the engine fire were ND. (Note: The MDCs were 

the same for the cabin and engine fire suppressions.) All exposures 

were well below applicable STELs or ceiling limits. Concentrations 

between the MDC and MQC are listed in Table 5 and subsequent 

tables but are in parentheses to point out that there is more 

uncertainty associated with these values than with concentrations 

above the MQC.
Health Hazard Evaluation Report 2008-0241-3113 Page 11

Results (continued)

Second Evaluation 

The goal of the second evaluation was to conduct a more 

thorough investigation of the chemical and particle hazards 

present during vehicle fire suppression by sampling for specific 

chemical compounds and characterizing particles in the air. Table 

6 provides the PBZ concentrations of aromatic hydrocarbons 

and aldehydes measured during the second evaluation. The PBZ 

concentrations of naphthalene, styrene, and acrolein were ND 

(below the respective MDCs of 0.94, 4.7, and 0.16 mg/m3

). Three 

samples of toluene and one sample of ethyl benzene had evidence 

of significant breakthrough, where the back section of the sampler 

collected >10% of the front section. These samples may have 

underestimated the actual air concentrations. Two of 15 PBZ 

samples measured formaldehyde above the NIOSH ceiling limit of 

0.12 mg/m3

.

Table 5. Personal breathing zone concentrations (mg/m3) of benzene and toluene measured during the cabin 

fire suppression on the first evaluation*

Job title Sampling time (min) Benzene Toluene

Nozzle operator 22 (0.13) (0.27)

Backup 22 ND (0.12)

Forcible entry 23 ND (0.12)

Officer 23 ND (0.20)

MDC 0.09 0.11

MQC 0.34 0.41

* Values in parentheses represent concentrations below the MQC but above the MDC.
Page 12 Health Hazard Evaluation Report 2008-0241--3113

Results (continued)

Table 7 presents the PBZ concentrations of isocyanates measured 

during the cabin fires on the second evaluation. Levels above the 

MDCs but below the MQCs were not reported by the analytical 

laboratory. Thus, ND represents concentrations below the 

respective MQCs. The PBZ concentrations of MDI, HDI, and 

IPDI were ND (below their respective MQCs of 1.8 μg/m3

). The 

Table 6. Personal breathing zone concentrations (mg/m3) of aromatic hydrocarbons and aldehydes measured 

during the second evaluation*

Job title Fire Sampling 

time (min) Benzene Ethyl benzene Toluene Xylene Formaldehyde

Nozzle operator 1 55 (0.08) ND 2.45 (0.12)† ND

Backup 1 52 (0.10) ND (0.26) ND (0.04)

Officer 1 58 ND ND 2.52‡ (0.10)† ND

Motor pump 

operator 1 43 ND ND (0.09)‡ ND ND

Duct holder 1 46 ND ND 4.30‡ ND ND

Nozzle operator 2 43 ND ND (0.14) ND (0.14)

Backup 2 40 ND ND (0.16) ND ND

Officer 2 46 ND ND (0.15) ND (0.05)†

Motor pump 

operator 2 48 ND ND 0.69 ND (0.06)

Duct holder 2 39 ND (0.10)‡ ND ND ND

Nozzle operator 3 40 (0.08) ND (0.19) ND ND

Backup 3 43 ND ND (0.09) ND (0.06)

Officer 3 34 (0.14) (0.15) (0.44) (0.25) ND

Motor pump 

operator 3 43 ND ND ND ND ND

Duct holder 3 32 (0.16) ND (0.14) ND 0.31

MDC 0.08 0.06 0.08 0.16 0.06

MQC 0.31 0.22 0.67 1.4 0.22

* Values in parentheses represent concentrations below the MQC but above the MDC.

†

 Calculated using a greater volume of air than that used to calculate the MDC.

‡

 Evidence of chemical breakthrough where the back section of the sampler collected >10% of the front section.
Health Hazard Evaluation Report 2008-0241-3113 Page 13

Results (continued) PBZ concentrations of MIC, EIC, and PIC were also ND (below 

their respective MQCs of 3.6 μg/m3).

TRIG is the concentration of all measurable isocyanate groups 

(N=C=O) in a sample of air. TRIG was calculated by multiplying 

the decimal percentage of isocyanate groups in the compound 

(the molecular weight of total isocyanate groups divided by the 

molecular weight of the compound) by the PBZ concentration 

(μg/m3

) of that compound and adding the resultant values for 

all measureable isocyanate compounds. Because ICA has the 

greatest proportion of the isocyanate group (98%), it had the 

greatest influence on the concentration of TRIG. The detection 

limit for ICA was used to calculate the MQC for TRIG. In theory, 

the MQC for TRIG could be considerably less than 17.5 μg/m3

. 

Table 7. Personal breathing zone concentrations (μg/m3) of isocyanates measured during the cabin fire 

suppression on the second evaluation

Job title* Fire Sample time 

(min) PHI TDI ICA TRIG

Nozzle operator 1 15 3.20 1.54 16.2† 17.7

Backup 1 15 ND ND ND ND

Officer 1 15 Sample excluded because of pump error

Duct holder 1 16 ND ND ND ND

Nozzle operator 2 14 ND ND 19.7 19.2

Backup 2 14 ND ND ND ND

Officer 2 14 ND ND ND ND

Duct holder 2 14 ND 7.68 28.6 31.6

Nozzle operator 3 17 Sample excluded because of pump error

Backup 3 17 ND ND ND ND

Officer 3 17 ND ND ND ND

Duct holder 3 18 ND ND ND ND

MQC 3.6 1.8 17.9 17.5

* The motor pump operator wore the same denuder for both the engine and cabin fires; thus, his exposures 

(which were all non-detectable) are not reported.

†

 Calculated using a greater volume of air than that used to calculate the MQC.
Page 14 Health Hazard Evaluation Report 2008-0241--3113

Results (continued) For example, using the detection limit for TDI, we calculated 

an MQC of 0.86 μg/m3. However, we cannot assume that ND 

concentrations for TRIG would represent levels so far below 17.5 

μg/m3

, especially because ICA was the most abundant isocyanate 

species and was present in all samples with any detectable levels of 

isocyanates.

Because three samples of TRIG were just below the Swedish STEL 

of 44 μg/m3

, we used statistical analysis to determine the likelihood 

of an overexposure (IHDataAnalyst V1.01, Exposure Assessment 

Solutions Inc., Morgantown, West Virginia). Maximum likelihood 

estimation was used for assigning values to the ND concentrations. 

According to this analysis, there is a 27% probability that the true 

95th percentile for the PBZ concentrations of TRIG is above the 

Swedish STEL.

CO exposures for the fire fighters suppressing vehicle fires (nozzle 

operator, backup, and officer) are illustrated in Figures E1–E3 in 

Appendix E. None of the instantaneous measurements exceeded 

the NIOSH ceiling limit of 200 ppm. However, one measurement 

(196 ppm) collected in the PBZ of a fire fighter performing backup 

was just below the NIOSH ceiling limit. Therefore, the potential 

for overexposure to CO cannot be discounted.

The area sampling results are presented in Table D3 in Appendix 

D. Toluene, benzene, and TRIG were most frequently detected 

but the majority of the contaminants were ND. All of the 

concentrations were below applicable STELs except for one sample 

that measured TRIG concentrations above the Swedish STEL of 

44 μg/m3

.

Particle exposure was primarily influenced by the position of 

the fire fighters relative to the wind direction. Increased particle 

exposures were observed during knockdown and overhaul phases 

of fire suppression. Figures E4–E6 in Appendix E show time 

series data for particle measurements collected during the vehicle 

fires (engine fires followed by cabin fires). Figure E7 in Appendix 

E shows the particle number concentrations by different size 

ranges during the second evaluation. According to this figure, 

the ultrafine particles (< 0.1 μm in diameter) dominated the 

particle counts. Fifteen-minute TWA concentrations from each 

of the vehicle fires are presented in Table 8. Maximum transient 

concentrations of 1.2 x 107

/cm3 for particle number, 4700 μm2/

cm3

 for active surface area, and 170 mg/m3 for respirable particle 

mass were obtained throughout all six fires.
Health Hazard Evaluation Report 2008-0241-3113 Page 15

Results (continued)

A summary of the weather conditions during the second evaluation 

is presented in Table D4 in Appendix D. The wind direction 

during fire suppression varied, but was predominately southerly 

with an average speed of 2.6 mph. The fire fighters attacked the 

fires mostly from the south or southeast direction. Thus, the 

wind tended to blow away from the fire fighters. Nevertheless, 

we observed instances when the fire fighters encountered the 

smoke plume because the winds shifted or because the fire fighters 

changed positions to gain better access to the fire. The temperature 

increased slightly throughout the day (75°F–79°F), while the 

relative humidity remained steady (average of 33%). According to 

the thermal images (Figures E8–E11 in Appendix E), the cabin 

fires were hotter than the engine fires, and some metal parts of the 

vehicles remained hot (> 200°F) after knockdown. All but one fire 

exceeded 1000°F.

Table 8. Particle measurements and CO concentrations for each vehicle fire expressed as 15-minute TWA 

concentrations

Number 

(/cm3

)

Respirable mass 

(mg/m3)

Active surface 

area

(mm2/cm3)

Photoelectric 

response

CO 

(ppm)

Vehicle 1

Engine Mean 55,700 0.53 100 30 1.3

Maximum 2,360,000 76 880 580 7.2

Cabin Mean 88,500 0.13 110 10 0.6

Maximum 1,443,000 12 560 60 1.7

Vehicle 2

Engine Mean 54,100 0.22 97 50 0.4

Maximum 2,945,000 37 940 1000 1.5

Cabin Mean 198,000 2.0 350 72 1.8

Maximum 6,950,000 170 2600 1400 8.8

Vehicle 3

Engine Mean 52,600 0.33 80 8.0 0.4

Maximum 1,380,000 51 680 97 1.6

Cabin Mean 324,000 5.9 490 21 7.0

Maximum 12,100,000 170 4700 340 62

Background* Mean 20,400 0.007 14 3.0 0.1

Maximum 24,700 0.011 20 5.0 0.3

* Background levels were determined by sampling the air prior to any of the vehicle fires.
Page 16 Health Hazard Evaluation Report 2008-0241--3113

Vehicle fires, although suppressed quickly, can release hundreds of 

toxic chemicals into the air. Vehicle fire emissions include organic 

compounds (e.g., benzene, formaldehyde, hydrogen cyanide) 

and inorganic compounds (e.g., CO, sulfur dioxide, hydrogen 

chloride). Many of these compounds can be acutely toxic. Particles 

of various sizes and composition will also likely be produced and 

may cause health effects over short exposure periods. Even after 

the fire is extinguished, the release of potentially harmful chemicals 

and particles may continue. The purpose of our evaluation 

was to identify and quantify some of the potential acutely toxic 

chemical and particle hazards present in the air during vehicle fire 

suppression.

This evaluation has several limitations. Measuring all the harmful 

substances emitted in vehicle fires is not feasible. For example, 

although sulfur dioxide and hydrogen chloride can be acutely 

toxic and are likely to be present in vehicle fire smoke, we did not 

sample for them simply because we did not want to overburden 

the fire fighters with too many sampling pumps. The sampling 

media we used also have limitations. For example, charcoal tubes 

and XAD-2 tubes are designed primarily to measure gases and 

vapors. Thus, gases and vapors adsorbed to particles may not have 

been quantified with the sampling methods we used. In addition, 

vehicle fires are extremely hot. We observed flames that exceeded 

1000°F and smoke that exceeded 300°F (see Figures E8 and E10 

in Appendix E). Even after the initial knockdown, some metal 

parts of the vehicles exceeded 200°F (see Figures E9 and E11 in 

Appendix E). Elevated ambient temperatures (> 100°F) can cause 

a portion of aromatic hydrocarbons to pass through charcoal 

tubes. We saw evidence of this in that 3 of 15 PBZ samples of 

toluene had significant breakthrough (where the back section of 

the sampler collected > 10% of the front section). One sample of 

ethyl benzene also showed significant breakthrough. Therefore, 

the PBZ concentrations of aromatic hydrocarbons we reported 

may underestimate the true concentrations. Benzene, toluene, 

and ethyl benzene are the most volatile aromatic hydrocarbons we 

measured, and as such, would be most vulnerable to the effects of 

elevated ambient temperatures. This temperature effect is unlikely 

for XAD-2 or denuders because they are designed to derivatize 

chemicals during sample collection.

The duct and blower system utilized for the direct reading particle 

sampling had some limitations. Although the duct inlet was 

Discussion
Health Hazard Evaluation Report 2008-0241-3113 Page 17

Discussion (continued) positioned close to the nozzle operator’s shoulder by an assisting 

fire fighter, measurements should not be construed as actual PBZ 

concentrations for the nozzle operator or any other fire fighters. 

The movement of the nozzle operator and other fire fighters during 

fire suppression made exposure assessment challenging, particularly 

because particle concentration gradients close to burning vehicles 

were expected to be great. Nevertheless, the data presented here 

do provide some indication of particle concentration, duration 

of exposure, and size of particles anticipated during vehicle fire 

suppression. One further limitation of this evaluation was that 

compositional information of the emitted particles was not 

investigated.

Despite the limitations of this evaluation, we were able to 

characterize the fire fighter exposures to select aromatic 

hydrocarbons, aldehydes, isocyanates, CO, and particles. During 

the second evaluation, we found a potential for overexposure 

to formaldehyde and TRIG during vehicle fire suppression. 

Quantifiable levels of TRIG were only present in the air during the 

cabin fire suppressions. This finding makes sense given the large 

proportion of isocyanate-based foams that are used in the vehicle 

cabins. Exposures to CO were generally well below the NIOSH 

ceiling limit of 200 ppm. However, one measurement of CO (196 

ppm) collected in the PBZ of the fire fighter performing backup 

during knockdown of an engine fire was just below the NIOSH 

ceiling limit (see Figure E1 in Appendix E). Thus, overexposure 

to CO is a possibility during vehicle fire suppression, especially 

when the fire fighters work close to the fires. All other PBZ 

concentrations were below applicable STELs or ceiling limits.

The chemical and particle levels we found were most likely 

influenced by the wind speed and direction. During the first 

evaluation, the wind was brisk (average of 14 mph) and blew away 

from 0he fire fighters. During the second evaluation, the wind 

was light (average of 2.6 mph) and blew in different directions 

(although predominantly away from the fire fighters). Therefore, we 

would expect greater exposures during the second evaluation than 

the first evaluation. Overall, the PBZ concentrations of toluene 

were higher during the second evaluation than the first evaluation. 

Concentrations of the other aromatic hydrocarbons could not be 

compared between evaluations because of the high percentage of 

ND concentrations.
Page 18 Health Hazard Evaluation Report 2008-0241--3113

Discussion (continued) The area air sampling results from the second evaluation also 

provided evidence that contaminants were transported by the 

wind. Benzene, toluene, and TRIG were found in area samples 

from each fire. Area samples were not collected north of the 

vehicle fires. Because the winds were predominately southerly, this 

was probably the area where contaminant concentrations were 

the greatest. Nevertheless, one area sample collected west of the 

third vehicle fire measured TRIG concentrations that exceeded 

the Swedish STEL (44 μg/m3

). This finding provides additional 

evidence of a potential for overexposure to TRIG during vehicle 

fire suppression.

All the fire fighters in this evaluation except the motor pump 

operator wore SCBAs. The motor pump operator did not wear an 

SCBA because he was > 50 feet upwind from the fires and needed 

to easily communicate on the radio with the other fire fighters. 

The motor pump operator’s PBZ concentrations, therefore, 

represent actual inhalation exposures. The motor pump operator 

was exposed to toluene and formaldehyde at concentrations 

below OELs. The source of these compounds could have been 

emissions from the vehicle fires or diesel exhaust from the fire 

apparatus [Ulfvarson et al. 1987; Smith et al. 2004; Mabilia et 

al. 2006]. For the other fire fighters, the PBZ concentrations we 

reported represent potential inhalation exposures due to the 

added protection of the SCBAs they wore. The OSHA assigned 

protection factor for a full facepiece SCBA used in positive 

pressure mode is 10,000 when fitted, maintained, and worn 

according to OSHA regulations [29 CFR 1910.134]; thus the 

inhalation exposures for the fire fighters who wore SCBAs are 

estimated to be 10,000 times lower than the PBZ concentrations 

we reported.

Fire fighters commonly do not wear SCBAs when responding to 

vehicle fires. According to an analysis by Austin et al. [2001], fire 

fighters in Montreal were estimated to wear SCBAs approximately 

50% of the time at structural fires, but only 6% of the time at all 

fires (which included vehicle fires). Possible reasons for not wearing 

an SCBA during vehicle fires include the following: vehicle fires 

tend to be suppressed quickly (within a few minutes) and thus, 

exposures are assumed to be minimal, donning an SCBA takes 

time and is cumbersome to wear, and the belief that breathing air 

should be saved for more intense fires when it is really needed. 

Even when SCBAs are worn for vehicle fires, they may be removed 

during overhaul.
Health Hazard Evaluation Report 2008-0241-3113 Page 19

Discussion (continued) Because fire fighters do not always wear SCBAs when responding 

to vehicle fires, the concentrations we measured indicate the 

potential for overexposure to some chemicals. In general, STELs 

and ceiling limits are intended to prevent acute health effects 

from short-term exposures. Short-term exposure to formaldehyde 

can cause eye and upper respiratory tract irritation [IPCS 2004]. 

Short-term exposure to isocyanates can irritate the respiratory tract 

and possibly lead to respiratory sensitization and occupational 

asthma [Chan-Yeung and Lam 1986]. Short-term exposure to CO 

can reduce the oxygen-carrying capacity of the blood, which may 

lead to asphyxiation or increase the risk for a cardiovascular event 

[IPCS 2007]. Chronic effects, such as cancer, generally require 

longer exposure periods. Cancer also has a latency period (10–30 

years), which is the time between first exposure to a carcinogen 

and clinical recognition of the disease [Rugo 2004]. Of the 

chemicals we sampled, benzene and formaldehyde are considered 

carcinogenic to humans [IARC 1982a, 1982b, 1987, 2006]. Certain 

PAHs (e.g., benzo[a]pyrene and benz[a]anthracene), which may 

be produced during incomplete combustion of organic materials, 

are considered probably carcinogenic to humans [IARC 1983]. 

Although we did not quantify PAHs, the photoelectric aerosol 

sensor responds most strongly to particle emissions with surfaces 

enriched with PAH compounds [Siegmann et al. 1999]. The strong 

elevations in photoelectric response observed throughout sampling 

were most likely derived from particle surfaces with adsorbed 

PAHs. For more information on the potential health effects of the 

substances we sampled, see Appendix C.
Page 20 Health Hazard Evaluation Report 2008-0241--3113

Hundreds of organic and inorganic compounds in gaseous and 

particulate form may be released during vehicle fires and therefore 

may present a health hazard for fire fighters. We evaluated fire 

fighter exposures to chemicals and particles during vehicle 

fire suppression training. We identified the primary gases and 

vapors present in vehicle fire emissions and quantified the PBZ 

concentrations of some of these substances. Because vehicle fires 

are suppressed quickly, we compared the PBZ concentrations to 

applicable STELs and ceiling limits. We found a potential for 

overexposure to formaldehyde, TRIG, and CO. Although no 

STELs or ceiling limits exist for particle concentrations, we found 

increased concentrations of particle number, respirable particle 

mass, and active particle surface area during knockdown and 

overhaul of the vehicle fires.

Based on our findings, we recommend the actions listed below to 

create a more healthful workplace. We encourage Miami Township 

Fire and Rescue to use a labor-management health and safety 

committee or working group to discuss the recommendations 

in this report and develop an action plan. Because the vehicle 

fire suppression training took place in a parking lot, engineering 

controls (e.g., exhaust ventilation) are not feasible. Instead, 

fire fighters must rely on PPE and administrative controls for 

protection.

Personal Protective Equipment

Proper use of PPE requires a comprehensive program, and calls 

for a high level of employee involvement and commitment to be 

effective. The use of PPE requires the choice of the appropriate 

equipment to reduce the hazard and the development of 

supporting programs such as training, change-out schedules, and 

medical assessment if needed.

1. Continue to use SCBAs when responding to vehicle fires. 

The fire fighters should don the SCBAs when they arrive at 

the scene and doff SCBAs only after overhaul is complete. 

This protocol should become written policy.

Conclusions

Recommendations
Health Hazard Evaluation Report 2008-0241-3113 Page 21

Recommendations

(continued) Administrative Controls 

Administrative controls are management-dictated work practices 

and policies to reduce or prevent exposures to workplace hazards. 

The effectiveness of administrative changes in work practices 

for controlling workplace hazards is dependent on management 

commitment and employee acceptance. Regular monitoring and 

reinforcement are necessary to ensure that control policies and 

procedures are not circumvented in the name of convenience or 

production.

1. Continue to position the motor pump operator and fire 

apparatus upwind of the vehicle fires to minimize exposures 

to the vehicle fire emissions.

2. Position the motor pump operator in an area upwind of the 

diesel exhaust from the fire apparatus. Diesel exhaust also 

contains hazardous substances.

ACGIH [2009]. Threshold limit values for chemical substances and 

physical agents and biological exposure indices. Cincinnati, OH: 

American Conference of Governmental Industrial Hygienists.

Ahrens M [2004]. U.S. vehicle fire trends and patterns. Quincy, 

MA: Fire Analysis and Research Division. National Fire Protection 

Association.

Austin CC, Dussault G, Ecobichon DJ [2001]. Municipal 

firefighter exposure groups, time spent at fires and use of selfcontained-breathing-apparatus. Am J Ind Med 40(6):683–692.

CFR. Code of Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the Federal Register.

Chan-Yeung M, Lam S [1986]. Occupational asthma. Am Rev 

Respir Dis 133(4):686–703.

EPA [1999]. Compendium Method TO-15, Determination of 

volatile organic compounds (VOCs) in air collected in speciallyprepared canisters and analyzed by gas chromatography/mass 

spectrometry (GC/MS). In: Compendium of methods for the 

determination of toxic organic compounds in ambient air. 

References
Page 22 Health Hazard Evaluation Report 2008-0241--3113

References (continued) Cincinnati, OH: Center for Environmental Research Information, 

Office of Research and Development, U.S. Environmental 

Protection Agency (EPA) Publication No. EPA/625/R-96/010b 

[http://www.epa.gov/ttnamtil/files/ambient/airtox/to-15.pdf].

Evans D, Ku B, Birch M, Dunn K [in press]. Aerosol 

characterization during carbon nanofiber production: mobile 

direct-reading sampling. Ann Occup Hyg.

HSE [1999]. EH 40/98, occupational exposure limits 199.8. 

Sudbury, England: Health and Safety Executive (HSE) Books.

IARC [1982a]. Monographs on the evaluation of the carcinogenic 

risks to humans: some industrial chemicals and dyestuffs. Vol. 29. 

Lyon, France: World Health Organization, International Agency 

for Research on Cancer [http://monographs.iarc.fr./ENG/

Monographs/vol29/volume29.pdf].

IARC [1982b]. Monographs on the evaluation of the carcinogenic 

risks to humans: some industrial chemicals and dyestuffs. Vol. 29. 

Lyon, France: World Health Organization, International Agency 

for Research on Cancer [http://monographs.iarc.fr./ENG/

Monographs/vol29/volume29.pdf].

IARC [1983]. Monographs on the evaluation of the carcinogenic 

risks to humans: polynuclear aromatic compounds, part 1, 

chemical, environmental and experimental data. Vol. 32. Lyon, 

France: World Health Organization, International Agency 

for Research on Cancer [http://monographs.iarc.fr./ENG/

Monographs/vol32/volume 32.pdf]. 

IARC [1987]. Monographs on the evaluation of the carcinogenic 

risks to humans: overall evaluations of carcinogenicity: an updating 

of IARC monographs volumes 1 to 42. Suppl. 7. Lyon, France: 

World Health Organization, International Agency for Research on 

Cancer [http://monographs.iarc.fr./ENG/Monographs/suppl7/

suppl7.pdf]. 

IARC [2006]. Monographs on the evaluation of the carcinogenic 

risks to humans: formaldehyde, 2-butoxyethanol and 1-tertbutoxypropan-2-ol. Vol. 88. Lyon, France: World Health 

Organization, International Agency for Research on Cancer 

[http://monographs.iarc.fr./ENG/Monographs/vol88/volume88.

pdf]. 
Health Hazard Evaluation Report 2008-0241-3113 Page 23

References (continued) IPCS (WHO/International Programme on Chemical Safety) 

[2004]. International Chemical Safety card: formaldehyde [http://

www.cdc.gov/niosh/ipcsneng/neng0023.html]. 

IPCS (WHO/International Programme on Chemical Safety) 

[2007]. International Chemical Safety card: carbon monoxide 

[http://www.cdc.gov/niosh/ipcsneng/neng0023.html]. 

Mabilia R, Cecinato A, Guerriero E, Possanzini M [2006]. 

Uncertainties of polynuclear aromatic hydrocarbon and carbonyl 

measurements in heavy-duty diesel emission. J Sep Sci 29(2):302–

307.

Marand A, Karlsson D, Dalene M, Skarping G [2005]. Solvent-free 

sampling with di-n-butylamine for monitoring of isocyanates in air. 

J Environ Monit 7(4):335–343.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. Barsen 

ME, ed. Cincinnati, OH: U.S. Department of Health and Human 

Services, Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health (NIOSH) Publication 

No. 2005-149.

NIOSH [2010]. NIOSH manual of analytical methods. 4th 

ed. Schlecht PC, O’Connor PF, eds. Cincinnati, OH: U.S. 

Department of Health and Human Services, Centers for Disease 

Control and Prevention, National Institute for Occupational Safety 

and Health, DHHS (NIOSH) Publication No. 94-113 (August 

1994); 1st Supplement Publication 96-135, 2nd Supplement 

Publication 98-119, 3rd Supplement Publication 2003-154. 

[http://www.cdc.gov/niosh/nmam]. 

Rugo H [2004]. Occupational cancer. In: LaDou J, ed. Current 

Occupational and Environmental Medicine. New York, NY: 

McGraw Hill Companies, Inc., pp. 229–267.

Siegmann K, Scherrer L, Siegmann HC [1999]. Physical and 

chemical properties of airborne nanoscale particles and how to 

measure the impact on human health. J Mol Struct-Theochem 

458(1–2):191–201.

Smith D, Spanel P, Dabill D, Cocker J, Rajan B [2004]. On-line 

analysis of diesel engine exhaust gases by selected ion flow tube 

mass spectrometry. Rapid Commun Mass Spectrom 18(23):2830–

2838.
Page 24 Health Hazard Evaluation Report 2008-0241--3113

References (continued) Swedish National Board of Occupational Safety and Health 

[2000]. Occupational exposure values, Arbetarskyddsstyrelsens 

forfattningssamling, AFS 2000:3, Liber, Stockholm.

Ulfvarson U, Alexandersson R, Aringer L, Svensson E, 

Hedenstierna G, Hogstedt C, Holmberg B, Rosen G, Sorsa M 

[1987]. Effects of exposure to vehicle exhaust on health. Scand J 

Work Environ Health 13(6):505–512.
Health Hazard Evaluation Report 2008-0241-3113 Page 25

Volatile Organic Compounds 

During the first evaluation, VOCs were sampled with evacuated stainless steel Summa canisters and TD 

tubes. The Summa canisters were used to collect 1 liter of gases and vapors from the vehicle fire emissions. 

The canisters under vacuum drew in 1 liter of air in less than 30 seconds. Particulate screens prevented 

particles from entering the canisters. The Summa canister samples were quantitatively analyzed for 75 

VOCs out of 189 hazardous air pollutants listed in Title III of the Clean Air Act Amendments of 1990 

[42 USC 85(i)(a)§7412] according to the EPA TO-15 Method [EPA 1999]. The TD tubes were used to 

sample air in the PBZs of the fire fighters. The TD tubes contained three beds of sorbent material: (1) 90 

milligrams of CarbopackTM Y, (2) 115 mg of Carbopack B, and (3) 150 mg of CarboxenTM. Aircheck 2000 

pumps (SKC Incorporated, Eighty Four, Pennsylvania) were used for drawing airflows of 200 cc/min 

through the TD tubes. The samples were qualitatively analyzed for various VOCs according to NIOSH 

Method 2549 [NIOSH 2010].

Aromatic Hydrocarbons and Aldehydes 

Calibrated SKC Aircheck 2000 pumps pulled 200 and 100 cc/min of air through the sampling media. 

Benzene, ethyl benzene, naphthalene, styrene, toluene, and xylenes were sampled with charcoal tubes 

(100 milligram/50 milligram) at a flow rate of 200 cc/min and analyzed with NIOSH Method 1501 

[NIOSH 2010]. Formaldehyde and acrolein were sampled with XAD-2 tubes treated with 2-hydroxymethyl 

piperazine (120 milligram/60 milligram) at a flow rate of 100 cc/min and analyzed by NIOSH Method 

2541 [NIOSH 2010]. However, to achieve better sensitivity, the XAD-2 tube samples were analyzed by gas 

chromatography equipped with a nitrogen phosphorous detector instead of the flame ionization detector 

as stated in NIOSH Method 2541.

Isocyanates 

The sampling and analytical method used to measure isocyanates is described elsewhere [Marand et al. 

2005]. The sampling media consisted of a denuder, a polypropylene tube (7 cm long, 0.8 cm diameter) 

attached to a 13 mm-polypropylene cassette. The inner wall of the tube was coated with DBA impregnated 

glass fiber filter (2.5 × 6 cm). The polypropylene cassette held a DBA impregnated glass fiber filter (13 

mm diameter, 0.3 μm pore size). A calibrated SKC Aircheck 2000 pump was used to draw a flow rate of 

200 cc/min through the tube and through the filter cassette. In theory, most gases, vapors, and aerosols 

are collected and derivatized in the filter cassette. However, MIC reacts too slowly with the reagent 

(DBA) to be collected solely with the filter cassette [Marand et al. 2005]. Thus, the primary purpose of 

the impregnated tube was to act as a denuder sampler for the low molecular weight monoisocyanates 

(e.g., MIC, EIC, ICA) and to enhance the derivatization efficiency by continuously replenishing the filter 

cassette with reagent [Marand et al. 2005]. The denuder samples were analyzed by the Institutet för Kemisk 

Analys Norden AB (Hässleholm, Sweden) under the direction of Dr. Gunnar Skarping according to the 

methodology described elsewhere [Marand et al. 2005].

Appendix A: Sampling and Analytical Methods
Page 26 Health Hazard Evaluation Report 2008-0241--3113

Appendix A: Sampling and Analytical Methods (continued)

Particles 

Particles were sampled near fire fighters attacking fires using 25 feet of 4-inch diameter flexible aluminum 

ducting attached to a particle sampling platform described in detail elsewhere [Evans et al. 2010]. The 

sampling platform allowed simultaneous and continuous measurement of particles generated from fires in 

real time by multiple instruments. These instruments could not have otherwise been used close to the fires 

or the water spray from fire hoses. A blower unit downstream of the sampling platform drew contaminants 

or smoke resulting from the fires through the flexible ducting. Mean air velocities of between 1050 and 

1300 ft/min were attained within the duct, resulting in contaminant residence times of approximately 

1 second from duct inlet to instrument sampling probes. Sampling probes and inlets were selected and 

oriented to minimize particle sampling errors within the duct.

Particle concentration metrics included number, active surface area, respirable mass, photoelectric 

response and particle size distribution from 7 nm to 10 μm, provided respectively by a condensation 

particle counter (TSI 3007, Shoreview, Minnesota) with dilution, a diffusion charger (DC 2000CE,

EcoChem Analytics, Murrieta, California), a photometer (TSI DustTrakTM 8520), a photoelectric aerosol 

sensor (PAS 2000CE, EcoChem Analytics, Murrieta, California), and an Electrical Low Pressure Impactor 

(ELPI, Dekati, Tampere, Finland). Air quality metrics (temperature, relative humidity, CO, and CO2

concentrations) were also monitored from inside the duct (TSI Q-TrakTM Plus 8554).

References 

EPA [1999]. Compendium Method TO-15, Determination of volatile organic compounds (VOCs) in air 

collected in specially-prepared canisters and analyzed by gas chromatography/mass spectrometry (GC/

MS). In: Compendium of methods for the determination of toxic organic compounds in ambient air. 

Cincinnati, OH: Center for Environmental Research Information, Office of Research and Development, 

U.S. Environmental Protection Agency (EPA) Publication No. EPA/625/R-96/010b [http://www.epa.gov/

ttnamitl/files/ambient/airtox/to-15.pdf]. 

 Evans D, Ku B, Birch M, Dunn K [in press]. Aerosol characterization during carbon nanofiber 

production: mobile direct-reading sampling. Ann Occup Hyg.

Marand A, Karlsson D, Dalene M, Skarping G [2005]. Solvent-free sampling with di-n-butylamine for 

monitoring of isocyanates in air. J Environ Monit 7(4):335–343.

NIOSH [2010]. NIOSH manual of analytical methods. 4th ed. Schlecht PC, O’Connor PF, eds. 

Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and 

Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 

94-113 (August 1994); 1st Supplement Publication 96-135, 2nd Supplement Publication 98-119, 3rd 

Supplement Publication 2003-154. [http://www.cdc.gov/niosh/nmam]. 
Health Hazard Evaluation Report 2008-0241-3113 Page 27

According to a report by the U.S. Fire Administration [U.S. Fire Administration 2002], from 1996 to 

1998, an average of 377,000 highway vehicle fires occurred, and nearly one quarter of all fire department 

responses during that time were to vehicle fires—more than the responses to residential property fires. 

Similarly, according to a report by the National Fire Protection Association [Ahrens 2004], in 2002, public 

fire departments responded to 329,500 vehicle fires, accounting for 20% of all reported fires, and since 

1980, reported vehicle fires have fallen only 30%, compared to a 51% drop in reported structural fires and 

a 44% drop in fires of all types.

Despite the commonness of vehicle fires, only a few studies characterizing the emissions from vehicle fires 

have been reported in the literature [Wichmann et al. 1995; Lonnermark and Blomqvist 2006]. Most 

notable was a study by Lonnermark and Blomqvist [2006] where automobiles were burned in a controlled 

setting. Investigators in this study reported potentially harmful levels of hydrogen chloride, sulfur dioxide, 

aromatic hydrocarbons (benzene), PAHs, aldehydes (formaldehyde), dioxins and furans, and isocyanates. 

Many more studies investigating fire fighter exposures during structural fires have been conducted [Gold 

et al. 1978; Treitman et al. 1980; Brandt-Rauf et al. 1988; Jankovic et al. 1991; Bolstad-Johnson et al. 2000; 

Austin et al. 2001]. High levels (in excess of STELs) of CO, formaldehyde, acrolein, hydrogen chloride, 

hydrogren cyanide, sulphuric acid, and hydrogen fluoride have been reported during knockdown of 

structural fires [Jankovic et al. 1991]. Similarly, high levels of CO, formaldehyde, acrolein, glutaraldehyde, 

benzene, nitrogen dioxide, sulphur dioxide, and PAHs have been reported during overhaul of structural 

fires when SCBAs are commonly removed [Bolstad-Johnson et al. 2000].

From a particulate emissions perspective, little data have been reported in the literature to date. In the 

Lonnemark et al. [2006] vehicle fire study, particle size distribution measurements indicated significant 

submicrometer components for both particle number and mass. These findings suggest that the particulate 

component of vehicle fire emissions is of a size capable of reaching the gas exchange regions of lungs, 

where clearance mechanisms are least effective. Furthermore, PAHs were also indicated in both the 

vapor and particulate phases. These small particles may therefore provide a vector for not only depositing 

potential carcinogens, such as PAHs, into the deep lung tissues, but also onto the skin.

References 

Ahrens M [2004]. U.S. vehicle fire trends and patterns. Quincy, MA: Fire Analysis and Research Division. 

National Fire Protection Association.

Austin CC, Wang D, Ecobichon DJ, Dussault G [2001]. Characterization of volatile organic compounds in 

smoke at municipal structural fires. J Toxicol Environ Health A 63(6):437–458.

Bolstad-Johnson DM, Burgess JL, Crutchfield CD, Storment S, Gerkin R, Wilson JR [2000]. 

Characterization of firefighter exposures during fire overhaul. AIHAJ 61(5):636–641.

Appendix B: Literature Review
Page 28 Health Hazard Evaluation Report 2008-0241--3113

Appendix B: Literature Review (continued)

Brandt-Rauf PW, Fallon LF, Jr., Tarantini T, Idema C, Andrews L [1988]. Health hazards of fire fighters: 

exposure assessment. Br J Ind Med 45(9):606–612.

Gold A, Burgess WA, Clougherty EV [1978]. Exposure of firefighters to toxic air contaminants. Am Ind 

Hyg Assoc J 39(7):534–539.

Jankovic J, Jones W, Burkhart J, Noonan G [1991]. Environmental study of firefighters. Ann Occup Hyg 

35(6):581–602.

Lonnermark A, Blomqvist P [2006]. Emissions from an automobile fire. Chemosphere 62(7):1043–1056.

Treitman RD, Burgess WA, Gold A [1980]. Air contaminants encountered by firefighters. Am Ind Hyg 

Assoc J 41(11):796–802.

U.S. Fire Administration [2002]. Topical fire research series, vol. 2, issue 4: Highway vehicle fires. [http://

www.usfa.fema.gov/nfdc/tfrs/htm].

Wichmann H, Lorenz W, Bahadir M [1995]. Release of PCDD/F and PAH during vehicle fires in traffic 

tunnels. Chemosphere 31(2):2755–2766.
Health Hazard Evaluation Report 2008-0241-3113 Page 29

In evaluating the hazards posed by workplace exposures, NIOSH investigators use both mandatory (legally 

enforceable) and recommended OELs for chemical, physical, and biological agents as a guide for making 

recommendations. OELs have been developed by Federal agencies and safety and health organizations to 

prevent the occurrence of adverse health effects from workplace exposures. Generally, OELs suggest levels 

of exposure that most employees may be exposed up to 10 hours per day, 40 hours per week for a working 

lifetime without experiencing adverse health effects. However, not all employees will be protected from 

adverse health effects even if their exposures are maintained below these levels. A small percentage may 

experience adverse health effects because of individual susceptibility, a preexisting medical condition, and/

or a hypersensitivity (allergy). In addition, some hazardous substances may act in combination with other 

workplace exposures, the general environment, or with medications or personal habits of the employee 

to produce health effects even if the occupational exposures are controlled at the level set by the exposure 

limit. Also, some substances can be absorbed by direct contact with the skin and mucous membranes in 

addition to being inhaled, which contributes to the individual’s overall exposure.

Most OELs are expressed as a TWA exposure. A TWA refers to the average exposure during a normal 8- 

to 10-hour workday. Some chemical substances and physical agents have recommended STEL or ceiling 

values where health effects are caused by exposures over a short period. Unless otherwise noted, the STEL 

is a 15-minute TWA exposure that should not be exceeded at any time during a workday, and the ceiling 

limit is an exposure that should not be exceeded at any time.

In the United States, OELs have been established by Federal agencies, professional organizations, state 

and local governments, and other entities. Some OELs are legally enforceable limits, while others are 

recommendations. The U.S. Department of Labor OSHA PELs (29 CFR 1910 [general industry]; 29 

CFR 1926 [construction industry]; and 29 CFR 1917 [maritime industry]) are legal limits enforceable in 

workplaces covered under the Occupational Safety and Health Act. NIOSH RELs are recommendations 

based on a critical review of the scientific and technical information available on a given hazard and the 

adequacy of methods to identify and control the hazard. NIOSH RELs can be found in the NIOSH Pocket 

Guide to Chemical Hazards [NIOSH 2005]. NIOSH also recommends different types of risk management 

practices (e.g., engineering controls, safe work practices, employee education/training, personal protective 

equipment, and exposure and medical monitoring) to minimize the risk of exposure and adverse health 

effects from these hazards. Other OELs that are commonly used and cited in the United States include 

the TLVs recommended by ACGIH, a professional organization, and the WEELs recommended by the 

American Industrial Hygiene Association®, another professional organization. The TLVs and WEELs 

are developed by committee members of these associations from a review of the published, peer-reviewed 

literature. They are not consensus standards. ACGIH TLVs are considered voluntary exposure guidelines 

for use by industrial hygienists and others trained in this discipline “to assist in the control of health 

hazards” [ACGIH 2009]. WEELs have been established for some chemicals “when no other legal or 

authoritative limits exist” [AIHA 2009].

Outside the United States, OELs have been established by various agencies and organizations and include 

both legal and recommended limits. Since 2006, the Berufsgenossenschaftliches Institut für Arbeitsschutz 

(German Institute for Occupational Safety and Health) has maintained a database of international 

Appendix C: Occupational Exposure Limits and Health Effects
Page 30 Health Hazard Evaluation Report 2008-0241--3113

Appendix C: Occupational Exposure Limits and Health Effects (continued)

OELs from European Union member states, Canada (Québec), Japan, Switzerland, and the United 

States available at http://www.dguv.de/bgia/en/gestis/limit_values/index.jsp. The database contains 

international limits for over 1250 hazardous substances and is updated annually.

Employers should understand that not all hazardous chemicals have specific OSHA PELs, and for some 

agents the legally enforceable and recommended limits may not reflect current health-based information. 

However, an employer is still required by OSHA to protect its employees from hazards even in the absence 

of a specific OSHA PEL. OSHA requires an employer to furnish employees a place of employment free 

from recognized hazards that cause or are likely to cause death or serious physical harm [Occupational 

Safety and Health Act of 1970 (Public Law 91–596, sec. 5(a)(1))]. Thus, NIOSH investigators encourage 

employers to make use of other OELs when making risk assessment and risk management decisions to 

best protect the health of their employees. NIOSH investigators also encourage the use of the traditional 

hierarchy of controls approach to eliminate or minimize identified workplace hazards. This includes, in 

order of preference, the use of: (1) substitution or elimination of the hazardous agent, (2) engineering 

controls (e.g., local exhaust ventilation, process enclosure, dilution ventilation), (3) administrative controls 

(e.g., limiting time of exposure, employee training, work practice changes, medical surveillance), and (4) 

personal protective equipment (e.g., respiratory protection, gloves, eye protection, hearing protection). 

Control banding, a qualitative risk assessment and risk management tool, is a complementary approach 

to protecting employee health that focuses resources on exposure controls by describing how a risk 

needs to be managed. Information on control banding is available at http://www.cdc.gov/niosh/topics/

ctrlbanding/. This approach can be applied in situations where OELs have not been established or can be 

used to supplement the OELs, when available.

Vehicle Fires 

Because vehicle fires are suppressed quickly (<15 minutes), STELs and ceiling limits should be used 

in determining safe levels of exposures. Tables 2 (on page 7) and 3 (on page 8) provide the STELs and 

ceiling limits for the chemicals we monitored in the PBZs of the fire fighters, except CO and acrylonitrile. 

The NIOSH ceiling limit for CO is 200 ppm [NIOSH 2005]. The NIOSH and OSHA ceiling limits for 

acrylonitrile are 22 mg/m3

 [NIOSH 2005]. The following section briefly summarizes the possible acute 

and chronic health effects from exposure to the compounds we sampled. Acute health effects from shortterm exposures are the basis for most STELs and ceiling limits. However, because vehicle fires may account 

for up to 20% of all fire responses [Ahrens 2004], the potential chronic health effects from long-term or 

repeated exposures are also meaningful.

Aromatic Hydrocarbons

Short-term exposures to toluene can irritate the eyes and respiratory tract and may cause effects on the 

central nervous system; long-term or repeated exposures may also cause effects on the central nervous 

system, enhance hearing damage from noise exposure, and result in toxicity to human reproduction or 
Health Hazard Evaluation Report 2008-0241-3113 Page 31

Appendix C: Occupational Exposure Limits and Health Effects (continued)

development [IPCS 2002a]. Short-term exposures to naphthalene can cause effects on the blood, including 

lesions of blood cells (hemolysis); long-term or repeated exposures can result in chronic hemolytic anemia 

or cataracts [IPCS 2005]. Naphthalene is also considered possibly carcinogenic to humans [IARC 2002]. 

Short-term exposures to styrene may cause irritation to the eyes, skin, and respiratory tract, as well as 

effects on the central nervous system; long term exposures can defat the skin and also affect the central 

nervous system and enhance hearing damage from noise exposure [IPCS 2006]. Short-term exposures 

to xylenes may irritate the eyes and skin and affect the central nervous system; long-term exposures can 

defat the skin, affect the central nervous system, and may result in toxicity to human reproduction or 

development [IPCS 2002b]. Short-term exposures to benzene can cause irritation to the eyes, skin, and 

respiratory tract, as well as effects on the central nervous system; long-term exposures can defat the skin, 

affect the bone marrow and immune system, and lead to the development of leukemia [IPCS 2003]. 

Benzene is considered carcinogenic to humans [IARC 1982, 1987]. Unlike most STELs that are based on 

acute health effects, the ACGIH TLV STEL for benzene is based on the potential excess risk of leukemia 

from the dose rate-dependent toxicity of the compound [ACGIH 2001].

Acrylonitrile 

Short-term exposures to acrylonitrile may cause irritation to the eyes, skin, and respiratory tract, as well as 

effects on the central nervous system; long-term exposures can have effects on the central nervous system 

and liver, and cause skin sensitization [IPCS 2001a]. Acrylonitrile is also considered possibly carcinogenic 

to humans [IARC 1999].

Aldehydes 

Short-term exposures to formaldehyde can cause severe eye and respiratory tract irritation. Pulmonary 

edema is also possible. Long-term or repeated exposures to formaldehyde may cause cancer [IPCS 2004]. 

Formaldehyde is considered carcinogenic to humans [IARC 2006]. Acrolein is primarily an acute toxin. It 

is severely irritating to the eyes, skin, and respiratory tract. High levels of exposure can cause pulmonary 

edema [IPCS 2001b].

Isocyanates 

Short-term exposures to isocyanates can cause irritation to the eyes, skin, and respiratory tract, and lead to 

asthma-like reactions, bronchitis, pneumonitis, and pulmonary edema [IPCS 1995]. Long-term or repeated 

exposures to isocyanates can cause respiratory sensitization and occupational asthma [Chan-Yeung and 

Lam 1986; IPCS 1995; ACGIH 2004]. Once sensitized, a worker can experience an asthmatic response 

from short-term exposures at levels below OELs [Chan-Yeung and Lam 1986; ACGIH 2004].
Page 32 Health Hazard Evaluation Report 2008-0241--3113

Appendix C: Occupational Exposure Limits and Health Effects (continued)

Carbon Monoxide 

Short-term exposures to CO may affect the oxygen carrying capacity of the blood, resulting in asphyxiation 

and an increased risk for cardiac disorders. Long-term or repeated exposures can affect the cardiovascular 

system, central nervous system, and possibly cause toxicity to human reproduction or development [IPCS 

2007].

Particles 

Mechanistic understanding of the health effects of fine particulate matter on the human respiratory and 

cardiovascular systems is still in its infancy. However, numerous epidemiologic studies over the last few 

decades have consistently shown strong associations between elevations in ambient fine particulate matter 

concentrations and increases in short-term hospital admissions (morbidity) and mortality rates in the 

general population [Dockery et al. 1993; Seaton et al. 1995; Pope and Dockery 2006]. Those with preexisting cardiovascular or respiratory disease, such as the young and elderly, are at greatest risk for adverse 

health outcomes.

References 

ACGIH [2001]. Benzene. In: Documentation of the threshold limit values and biological exposure indices. 

Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [2004]. Toluene-2,4 or 2,6-diisocyanate (or as a mixture). In: Documentation of the threshold 

limit values and biological exposure indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

ACGIH [2009]. 2009 TLVs® and BEIs®: threshold limit values for chemical substances and physical 

agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

Ahrens M [2004]. U.S. vehicle fire trends and patterns. Quincy, MA: Fire Analysis and Research Division. 

National Fire Protection Association.

AIHA [2009]. AIHA 2009 Emergency response planning guidelines (ERPG) and workplace environmental 

exposure levels (WEEL) handbook. Fairfax, VA: American Industrial Hygiene Association.

CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Office of the 

Federal Register.

Chan-Yeung M, Lam S [1986]. Occupational asthma. Am Rev Respir Dis 133(4):686–703.
Health Hazard Evaluation Report 2008-0241-3113 Page 33

Appendix C: Occupational Exposure Limits and Health Effects (continued)

Dockery DW, Pope CA 3rd, Xu X, Spengler JD, Ware JH, Fay ME, Ferris BG, Jr., Speizer FE [1993]. An 

association between air pollution and mortality in six U.S. cities. N Engl J Med 329(24):1753–1759.

IARC [1982]. Monographs on the evaluation of the carcinogenic risks to humans: some industrial 

chemicals and dyestuffs. Vol. 29. Lyon, France: World Health Organization, International Agency for 

Research on Cancer [http://monographs.iarc.fr/ENG/Monographs/vol29/volume29.pdf].

IARC [1987]. Monographs on the evaluation of the carcinogenic risks to humans: overall evaluations of 

carcinogenicity: an updating of IARC monographs volumes 1 to 42. Suppl. 7. Lyon, France: World Health 

Agency for Research on Cancer [http://monographs.iarc.fr/ENG/Monographs/suppl7/suppl7.pdf].

IARC [1999]. Monographs on the evaluation of the carcinogenic risks to humans: re-evaluation of some 

organic chemicals, hydrazine, and hydrogen peroxide. Vol. 71. Lyon, France: World Health Organization, 

International Agency for Research on Cancer [http://monographs.iarc.fr/ENG/Monographs/vol82/

mono82-8.pdf].

IARC [2002]. Monographs on the evaluation of the carcinogenic risks to humans: naphthalene. Vol. 

82. Lyon, France: World Health Organization, International Agency for Research on Cancer [http://

monographs.iarc.fr/ENG/Monographs/vol82/mono82-8.pdf].

IARC [2006]. Monographs on the evaluation of the carcinogenic risks to humans: formaldehyde, 

2-butoxyethanol and 1-tert-butoxypropan-2-ol. Vol. 88. Lyon, France: World Health Organization, 

International Agency for Research on Cancer [http://monographs.iarc.fr/ENG/Monographs/vol88/

volume88.pdf].

IPCS (WHO/International Programme on Chemical Safety) [1995]. International Chemical Safety card: 

2,4-toluene diisocyanate [http://www.cdc.gov/niosh/ipcsneng/neng0339.html].

IPCS (WHO/International Programme on Chemical Safety) [2001a]. International Chemical Safety card: 

acrylonitrile [http://www.cdc.gov/niosh/ipcsneng/neng0092.html].

IPCS (WHO/International Programme on Chemical Safety) [2001b]. International Chemical Safety card: 

acrolein [http://www.cdc.gov/niosh/ipcsneng/neng0090.html].

IPCS (WHO/International Programme on Chemical Safety) [2002a]. International Chemical Safety card: 

toluene [http://www.cdc.gov/niosh/ipcsneng/neng0078.html].

IPCS (WHO/International Programme on Chemical Safety) [2002b]. International Chemical Safety card: 

m-xylene [http://www.cdc.gov/niosh/ipcsneng/neng0085.html].

IPCS (WHO/International Programme on Chemical Safety) [2003]. International Chemical Safety card: 

benzene [http://www.cdc.gov/niosh/ipcsneng/neng0015.html].
Page 34 Health Hazard Evaluation Report 2008-0241--3113

Appendix C: Occupational Exposure Limits and Health Effects (continued)

IPCS (WHO/International Programme on Chemical Safety) [2004]. International Chemical Safety card: 

formaldehyde [http://www.cdc.gov/niosh/ipcsneng/neng0275.html].

IPCS (WHO/International Programme on Chemical Safety) [2005]. International Chemical Safety card: 

naphthalene [http://www.cdc.gov/niosh/ipcsneng/neng0667.html].

IPCS (WHO/International Programme on Chemical Safety) [2006]. International Chemical Safety card: 

styrene [http://www.cdc.gov/niosh/ipcsneng/neng0073.html].

IPCS (WHO/International Programme on Chemical Safety) [2007]. International Chemical Safety card: 

carbon monoxide [http://www.cdc.gov/niosh/ipcsneng/neng0023.html].

NIOSH [2005]. NIOSH pocket guide to chemical hazards. Barsen ME, ed. Cincinnati, OH: U.S. 

Department of Health and Human Services, Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health (NIOSH) Publication No. 2005-149.

Pope CA 3rd, Dockery DW [2006]. Health effects of fine particulate air pollution: lines that connect. J Air 

Waste Manag Assoc 56(6):709–742.

Seaton A, MacNee W, Donaldson K, Godden D [1995]. Particulate air pollution and acute health effects. 

Lancet 345(8943):176–178.
Health Hazard Evaluation Report 2008-0241-3113 Page 35

Appendix D: Tables

Table D1. Ordered list of the 15 most abundant volatile organic compounds measured in the engine fire smoke with 

Summa canisters during the first evaluation

Order Startup Conc. Knockdown Conc. Overhaul Conc.

 (mg/m3) (mg/m3) (mg/m3) 

1 Benzene 5.2 Toluene 9.3 Dichlorodifluromethane 48

2 Dichlorodifluromethane 5.1 m,p-Xylenes 6.2 Benzene 11

3 Propene 3.3 1,2,4-Trimethyl 

benzene 4.2 Propene 11

4 1,3-Butadiene 2.3 Styrene 3.3 1,3-Butadiene 4.8

5 Naphthalene 1.4 o-Xylene 2.9 Acetone 3.8

6 Toluene 1.4 Dichlorodifluromethane 2.4 Toluene 3.8

7 Styrene 0.83 Ethyl benzene 2.2 Styrene 1.6

8 Acrolein 0.56 Benzene 1.6 Acrolein 1.4

9 Methyl methacrylate 0.44 1,3,5-Trimethyl 

benzene 1.4 Chloromethane 1.2

10 Acetone 0.40 4-Ethyltoluene 1.4 Naphthalene 1.2

11 Ethanol 0.40 n-Hexane 1.1 1,2-Dichloroethane 1.1

12 Chloromethane 0.33 Propene 0.91 m,p-Xylenes 0.97

13 Acrylonitrile 0.32 n-Heptane 0.87 Acrylonitrile 0.77

14 Acetonitrile 0.28 Acetone 0.84 Acetonitrile 0.70

15 m,p-Xylenes 0.25 Ethanol 0.72 Ethanol 0.67
Page 36 Health Hazard Evaluation Report 2008-0241--3113

Appendix D: Tables (continued)

Table D2. Ordered list of the 15 most abundant volatile organic compounds measured in the cabin fire smoke 

with Summa canisters during the first evaluation

Order Startup Conc. 

(mg/m3

) Knockdown Conc. (mg/m3) Overhaul Conc. (mg/m3)

1 Benzene 60 Toluene 4.6 Toluene 0.95

2 Acrylonitrile 27 Styrene 2.3 Styrene 0.45

3 Propene 18 m,p-Xylenes 2 Benzene 0.38

4 Acrolein 15 Acetone 1.9 m,p-Xylenes 0.33

5 Acetonitrile 14 n-Hexane 1.5 n-Hexane 0.31

6 Styrene 14 Benzene 1.4 Acetone 0.3

7 Acetone 12 Propene 1.4 n-Heptane 0.18

8 Chloromethane 11 n-Heptane 0.84 Naphthalene 0.17

9 Naphthalene 10 Methyl methacrylate 0.81 Propene 0.16

10 Toluene 10 o-Xylene 0.72 1,2-

Dichloroethane 0.14

11 1,3-Butadiene 6.8 1,2,4-Trimethyl 

benzene 0.70 o-Xylene 0.12

12 Vinyl chloride 3.7 Ethyl benzene 0.70 Ethyl benzene 0.12

13 Vinyl acetate 1.5 1,2-Dichloroethane 0.67 Acrylonitrile 0.07

14 Ethyl benzene 1.4 Acrylonitrile 0.38 1,3-Butadiene 0.05

15 2-Butanone 1.1 1,3-Butadiene 0.25 Chloromethane 0.05
Health Hazard Evaluation Report 2008-0241-3113 Page 37

Appendix D: Tables (continued)

Table D3. Area air sampling results*

Fire Sample 

location

Benzene 

(mg/m3)

Toluene 

(mg/m3)

MIC 

(μg/m3)

TDI 

(μg/m3)

ICA 

(μg/m3)

TRIG 

(μg/m3)

1 West (0.11) (0.07) ND ND 14.8 14.5

1 South ND 3.68 ND ND 6 5.9

1 East ND ND ND ND ND ND

2 West (0.06) (0.10) ND ND ND ND

2 South ND ND ND ND ND ND

2 East ND ND ND ND ND ND

3 West (0.21) (0.16) 8.8 3 60.2 66.8

3 South ND ND ND ND ND ND

3 East ND ND ND ND ND ND

MDC† 0.07 0.06 N/A N/A N/A N/A

MQC 0.24 0.51 1.2 0.6 6.0 5.8

* Values in parentheses represent concentrations above the MDC but below the MQC.

†

 The analytical laboratory that analyzed the isocyanate samples did not provide an MDC or report values 

below the MQC.
Page 38 Health Hazard Evaluation Report 2008-0241--3113

Appendix D: Tables (continued)

Table D4. Summary of weather conditions during vehicle fire suppressions for the second evaluation

Wind 

Vehicle fire 1 

(75°F, 34% RH*)

Vehicle fire 2 

(78°F, 31% RH)

Vehicle fire 3 

(79°F, 33% RH)

Minutes 

at wind 

direction

Average 

wind speed 

(mph)

Minutes 

at wind 

direction

Average 

wind speed 

(mph)

Minutes 

at wind 

direction

Average 

wind speed 

(mph)

Southeast 8 3.6 2 2.7 0 N/A

South 6 2.9 1 3.3 11 1.7

Southwest 2 3.1 3 2.4 3 1.2

West 1 2.1 8 3.0 1 1.7

Northwest 0 N/A 2 2.1 2 2.1

North 0 N/A 0 N/A 0 N/A

Northeast 1 3.3 0 N/A 0 N/A

East 2 3.1 2 1.9 0 N/A

* RH = relative humidity
Health Hazard Evaluation Report 2008-0241-3113 Page 39

Appendix E: Figures

Figure E1. Personal breathing zone concentrations of CO during the first vehicle fire 

suppression on the second evaluation.

Figure E2. Personal breathing zone concentrations of CO during the second 

vehicle fire suppression on the second evaluation.
Page 40 Health Hazard Evaluation Report 2008-0241--3113

Appendix E: Figures (continued)

Figure E3. Personal breathing zone concentrations of CO during the third vehicle 

fire suppression on the second evaluation.

Figure E4. Particle measurements collected during the first vehicle fire suppression 

on the second evaluation.
Health Hazard Evaluation Report 2008-0241-3113 Page 41

Appendix E: Figures (continued)

Figure E5. Particle measurements collected during the second vehicle fire 

suppression on the second evaluation.
Page 42 Health Hazard Evaluation Report 2008-0241--3113

Appendix E: Figures (continued)

Figure E7. Particle number concentrations for different particle size ranges (< 0.1 μm, 0.1–1 μm, 

and 1–10 μm in diameter) throughout the day during the second evaluation.

Figure E6. Particle measurements collected during the third vehicle fire suppression 

on the second evaluation.
Health Hazard Evaluation Report 2008-0241-3113 Page 43

Appendix E: Figures (continued)

Figure E8. Thermal image of engine fire before knockdown.

Figure E9. Thermal image of engine fire after knockdown.
Page 44 Health Hazard Evaluation Report 2008-0241--3113

Appendix E: Figures (continued)

Figure E10. Thermal image of cabin fire before knockdown.

Figure E11. Thermal image of cabin fire after knockdown.
Health Hazard Evaluation Report 2008-0241-3113 Page 45

Acknowledgments and

Availability of Report

The Hazard Evaluations and Technical Assistance Branch 

(HETAB) of the National Institute for Occupational Safety and 

Health (NIOSH) conducts field investigations of possible health 

hazards in the workplace. These investigations are conducted 

under the authority of Section 20(a)(6) of the Occupational Safety 

and Health (OSHA) Act of 1970, 29 U.S.C. 669(a)(6) which 

authorizes the Secretary of Health and Human Services, following 

a written request from any employer or authorized representative 

of employees, to determine whether any substance normally found 

in the place of employment has potentially toxic effects in such 

concentrations as used or found. HETAB also provides, upon 

request, technical and consultative assistance to federal, state, and 

local agencies; labor; industry; and other groups or individuals to 

control occupational health hazards and to prevent related trauma 

and disease.

The findings and conclusions in this report are those of the 

authors and do not necessarily represent the views of NIOSH. 

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do not constitute NIOSH endorsement of 

the sponsoring organizations or their programs or products. 

Furthermore, NIOSH is not responsible for the content of these 

websites. All Web addresses referenced in this document were 

accessible as of the publication date.

This report was prepared by Kenneth W. Fent and James Couch 

of HETAB, Division of Surveillance, Hazard Evaluations and 

Field Studies (DSHEFS) and Douglas E. Evans of Engineering 

and Physical Hazards Branch, Division of Applied Research 

and Technology (DART). Industrial hygiene field assistance was 

provided by Manny Rodriguez, Chad Dowell, and Donnie Booher 

of DSHEFS. Photography assistance was provided by Fariba 

Nourian of DART. Videography was provided by Charles Urban 

of the Office of the Director. Analytical support was provided 

by Gunnar Skarping and colleagues at the Institutet för Kemisk 

Analys Norden AB, Bureau Veritas North America, and Columbia 

Analytical Services. Health communication assistance was provided 

by Stefanie Evans of DSHEFS and Amanda Harney of the Office 

of the Director. Editorial assistance was provided by Ellen Galloway 

and desktop publishing was performed by Robin Smith of 

DSHEFS.
Page 46 Health Hazard Evaluation Report 2008-0241--3113

Acknowledgments and

 Availability of Report 

 (continued) Copies of this report have been sent to employee and management 

representatives at the Miami Township Fire and Rescue in Yellow 

Springs, Ohio, the Ohio Department of Health, and the OSHA 

Regional Office. This report is not copyrighted and may be freely 

reproduced. The report may be viewed and printed at http://www.

cdc.gov/niosh/hhe/. Copies may be purchased from the National 

Technical Information Service (NTIS) at 5825 Port Royal Road, 

Springfield, Virginia 22161.
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Below is a recommended citation for this report:

NIOSH [2010]. Health hazard evaluation report: evaluation of chemical and particle 

exposures during vehicle fire suppression training, Yellow Springs, OH. By Fent 

KW, Evans DE, Couch J. Cincinnati, OH: U.S. Department of Health and Human 

Services, Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HETA No. 2008-0241- 3113.

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