HETA 99-0266-2850

Costa Mesa Fire Department

Costa Mesa, California

Kevin C. Roegner, MPH, CIH

W. Karl Sieber, Ph.D.

Alan Echt, MPH, CIH

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/reports

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/reports

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.

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/reports
ii

PREFACE

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. Mention of company names or products does not constitute endorsement

by NIOSH.

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT

This report was prepared by Kevin C. Roegner of HETAB, Division of Surveillance, Hazard Evaluations and

Field Studies (DSHEFS). Field assistance was provided by Alan Echt of the Engineering and Physical

Hazards Branch, Division of Applied Research Technology; Joshua Harney, Robert McCleery, and Kristin

Gwin of HETAB, DSHEFS. Analytical support was provided by DataChem Laboratories. Desktop

publishing was performed by Ellen Blythe and David Butler. Review and preparation for printing were

performed by Penny Arthur.

Copies of this report have been sent to employee and management representatives of the City of Costa Mesa

Fire Department and the OSHA Regional Office. This report is not copyrighted and may be freely

reproduced. Single copies of this report will be available for a period of three years from the date of this

report. To expedite your request, include a self-addressed mailing label along with your written request to:

NIOSH Publications Office

4676 Columbia Parkway

Cincinnati, Ohio 45226

800-356-4674

After this time, copies may be purchased from the National Technical Information Service (NTIS) at

5825 Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may be

obtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall be

posted by the employer in a prominent place accessible to the employees for a period

of 30 calendar days.
iii

Highlights of the NIOSH Health Hazard Evaluation

Evaluation of Diesel Exhaust Controls

The Costa Mesa Fire Department asked NIOSH to evaluate the effectiveness of ceramic diesel

exhaust filters installed on department vehicles at controlling diesel exhaust exposures in fire

stations.

What NIOSH Did A

# We conducted a study in stations 3 and 5. A

# We collected air samples for diesel soot

and gases emitted from the apparatuses

before the filters were installed. A

# We collected samples for diesel soot after

the filters were installed. A

# We compared the amount of soot before

filter installation to the amount after

filter installation. A

# We observed the number of runs that

each apparatus made during the survey. A

# We looked at the ventilation systems in

each station. A

What NIOSH Found A

# The greatest soot concentrations were in

the apparatus bay. Firefighter exposures

to the exhaust were low before the filter

installation. A

# With the possible exception of nitrogen

dioxide (NO2), gas concentrations in the

bay were low before the filters were

installed.

A

# Installation of the ceramic filters reduced

diesel soot concentrations in the bay by

roughly 75–90%. A

# The ventilation system in station 3 kept

the living quarters under positive

pressure all of the time. The ventilation

system in station 5 kept the living

quarters under positive pressure some of

the time. A

What Costa Mesa Fire

Department Can Do A

# If diesel exhaust is a concern at other

stations, consider installing ceramic

diesel exhaust filters at those stations. A

# Provide more structured training and

information exchange in the future if

diesel exhaust controls are installed at

other stations. A

What the Costa Mesa

Firefighters Can Do A

# Leave the toggle switch for the ceramic

filter controls in the “on” position.

HHE Supplement

What To Do For More Information:

We encourage you to read the full report. If you would

like a copy, either ask your health and safety

representative to make you a copy or call

1-513/841-4252 and ask for

 HETA Report # 99-0266-2850
iv

Health Hazard Evaluation Report 99-0266-2850

Costa Mesa Fire Department

Costa Mesa, California

May 2001

Kevin C. Roegner, MPH, CIH

Karl Sieber, Ph.D.

Alan Echt, MPH, CIH

SUMMARY

On August 4, 1999, the National Institute for Occupational Safety and Health (NIOSH) received a request

from the Costa Mesa Fire Department (CMFD), located in Costa Mesa, California, to conduct a health hazard

evaluation (HHE). The CMFD was planning to install diesel exhaust filtration systems on some of their

apparatus and wanted NIOSH to evaluate the effectiveness of the controls.

In response to the request, NIOSH conducted pre- and post-control evaluations of diesel exhaust in two fire

stations. The pre-control evaluations were conducted on November 8–11, 1999. Samples were collected to

characterize contaminant concentrations at the fire stations, and to provide base line data for determining the

effectiveness of the ceramic exhaust filters at controlling these contaminants. Airborne concentrations of

elemental carbon (Ce), sulfur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), and volatile organic

compounds (VOCs) were measured. After the ceramic filters were installed on the engines, a follow-up

evaluation was conducted on March 14–17, 2000, to determine the control’s effectiveness in reducing diesel

soot (measured as Ce) in the fire stations. 

In the initial survey, only trace concentrations of Ce were measured in personal breathing zone (PBZ) samples

at each station. Concentrations of Ce in the living quarters of each station were mostly in the none detected

to trace range as well. The 12 Ce area samples collected in the apparatus bay of each station had mean

concentrations of 6.1 micrograms per cubic meter (:g/m3

) in station 3, and 15.6 :g/m3 in station 5.

SO2 was not detected in any spot samples collected in the apparatus bay of either station. This indicates that

the concentration of SO2 in the bay did not exceed 0.1 ppm as the apparatus entered and departed the station.

NO concentrations in the apparatus bay of both stations were all below the minimum detectible concentration

(MDC). This indicates that all concentrations were below 0.5 ppm as an 8-hour time weighted average, which

is well below the current evaluation criteria. 
v

Low concentrations of several organic chemicals were identified. Identified chemicals included methyl

t-butyl ether, C4–C7 alkanes, benzene, toluene, and xylenes. Concentrations of benzene and xylene were

quantified, and were well below current exposure criteria. 

In the post-control evaluation, Ce was not detected on 12 of 16 area samples collected in the bay of station 3.

Four area samples had a trace amount of Ce, indicating that Ce concentrations in the bay were between the

MDC of 1.3 :g/m3

 and the minimum quantifiable concentration (MQC) of 5.1 :g/m3. Ce was not detected

on 11 of 16 area samples collected during the post-control sampling campaign at station 5. Trace

concentrations of Ce were detected in four area samples, indicating that Ce concentrations for these samples

ranged from 1.3 to 5.1 :g/m3

. A significant reduction in geometric mean Ce concentrations in the apparatus

bay of both stations was evident in the data. The reductions were 76% in station 3 and 91% in station 5.

The NIOSH environmental assessment of diesel exhaust in two fire stations found that concentrations of diesel

exhaust gas-phase components were low prior to the installation of engineering controls. Personal exposures to

diesel exhaust particulate-phase components in these two fire stations were also low because the quantities of Ce

generated were moderate and because firefighters and paramedics did not spend very much time in the apparatus

bay. However, geometric mean concentrations of Ce in the two bays were reduced by 76% and 91% after the

ceramic diesel exhaust filters were installed. NIOSH researchers concluded that, in stations with pull-through

apparatus bays, the ceramic filters are effective at reducing the emission of diesel soot.

Recommendations were made for maintaining positive pressure in the living quarters relative to the bay and for a

more formalized means of training and information exchange about engineering controls, should they be installed

at other stations.

Keywords: SIC 9224 (Fire Protection), diesel exhaust control, fire stations, ceramic filters, elemental carbon
vi

TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Acknowledgments and Availability of Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

HHE Supplement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

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

Health Effects of Diesel Exhaust ...................................................... 1

Engineering Control Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Methods ........................................................................... 3

Station Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Environmental Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Ventilation Assessment ............................................................. 4

Statistical Methods ................................................................ 4

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Pre-Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Station 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Elemental Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sulfur Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Nitrogen Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Volatile Organic Compounds .................................................. 6

Ventilation Assessment ....................................................... 6

Station 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Elemental Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Nitrogen Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Volatile Organic Compounds .................................................. 6

Sulfur Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Ventilation Assessment ....................................................... 7

Post-Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Elemental Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Station 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Station 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Health Hazard Evaluation Report No. 99-0266-2850 Page 1

INTRODUCTION

On August 4, 1999, the National Institute for

Occupational Safety and Health (NIOSH) received a

request from the Costa Mesa Fire Department

(CMFD), located in Costa Mesa, California, to

conduct a health hazard evaluation (HHE). The

CMFD was planning to install diesel exhaust

filtration systems on some of their apparatus and

wanted NIOSH to evaluate the effectiveness of the

control.

In response to the request, NIOSH worked with the

CMFD to select stations within the department that

would be most appropriate for the study. NIOSH

then conducted a pre- and a post-control evaluation

of diesel exhaust in two fire stations. Site visits were

made to document levels of the gas-phase and

particulate-phase (soot) constituents of the diesel

exhaust, and to evaluate the control’s effectiveness at

reducing soot exposures at the fire stations. Airborne

concentrations were obtained for elemental carbon

(Ce), sulfur dioxide (SO2), nitric oxide (NO), nitrogen

dioxide (NO2), and volatile organic compounds

(VOCs). The first site visit was conducted on

November 8–11, 1999, before the ceramic filters

were installed on the engines housed at two stations.

A post-control evaluation was conducted on March

14–17, 2000.

Health Effects of Diesel

Exhaust

Diesel engines function by combusting liquid fuel

without spark ignition. Air is compressed in the

combustion chamber, fuel is introduced, and ignition

is accomplished by the heat of compression. The

emissions from diesel engines consist of a complex

mixture, including gaseous and particulate fractions.

The composition of the mixture varies greatly with

fuel and engine type, load cycle, maintenance,

tuning, and exhaust gas treatment. The gaseous

constituents include carbon dioxide (CO2), carbon

monoxide (CO), NO, NO2, SO2, and VOCs (e.g.,

ethylene, formaldehyde, methane, benzene, phenol,

acrolein, and polynuclear aromatic

hydrocarbons).1,2,3,4 The particulate fraction (soot) is

composed of solid carbon cores, produced during the

combustion process, which tend to combine to form

chains of particles or aggregates, the largest of which

are in the respirable range (more than 95% are less

than 1 micron in size).5

 Estimates indicate that as

many as 18,000 different substances resulting from

the combustion process may be adsorbed onto these

particulates.6

 The adsorbed material contains

15–65% of the total particulate mass and includes

compounds such as polynuclear aromatic

hydrocarbons, a number of which are known

mutagens and carcinogens.4,5,7,8

Many of the individual components of diesel exhaust

are known to have toxic effects. The following

health effects have been associated with some of the

components of diesel exhaust: (1) pulmonary

irritation from oxides of nitrogen; (2) irritation of the

eyes and mucous membranes from SO2, phenol,

sulfuric acid, sulfate aerosols, and acrolein; and (3)

cancer in animals from polynuclear aromatic

hydrocarbons. Several studies confirm an

association between exposure to whole diesel

exhaust and lung cancer in rats and mice.5

 Limited

epidemiological evidence suggests an association

between occupational exposure to diesel exhaust

emissions and lung cancer.9

 The agreement of

current toxicological and epidemiological evidence

led NIOSH in 1988 to recommend that whole diesel

exhaust be regarded as a “potential occupational

carcinogen,” as defined in the Occupational Safety

and Health Administration’s (OSHA) Cancer Policy

(“Identification, Classification, and Regulation of

Potential Occupational Carcinogens,” 29 CFR

1990).5

 Accordingly, NIOSH recommends that

exposures be controlled to the lowest feasible

concentration. Although OSHA has exposure limits

for some of the individual components of diesel

exhaust (i.e., NO2, xylene, and CO), a permissible

exposure limit (PEL) has not been established for

whole diesel exhaust. The American Conference of

Governmental Industrial Hygienists (ACGIH®) has

proposed, but not yet adopted, a threshold limit value

(TLV®) of 20 micrograms per cubic meter (:g/m3

)

for diesel exhaust emissions.10 

Engineering Control Options
Page 2 Health Hazard Evaluation Report No. 99-0266-2850

There are technologies available for controlling

diesel exhaust emissions into fire stations. These

technologies include exhaust filtration systems,

tailpipe exhaust ventilation, and dilution ventilation

systems. A summary of each technology is offered

below. 

Engine exhaust filters are designed to remove

particulate from the exhaust stream. The filters are

installed in the exhaust system or at the tailpipe. One

commercially available filter system consists of a

porous ceramic filter, a diverter valve, and an

electronic control module. The diverter valve is

installed in the exhaust pipe and directs the exhaust

through the ceramic filter when the engine is started.

After a preset time, usually between 20 seconds and

3 minutes, the electronic control vents the exhaust to

the exhaust pipe, bypassing the ceramic filter. The

timer should be set to allow enough time for the

truck to exit the fire station. When the truck is

shifted into reverse to back into the garage, the

electronic control again routes the exhaust fumes

through the filter. The ceramic filter weighs between

20 and 30 pounds and collects about 2 pounds of

particulate before requiring servicing. The

approximate cost for one filter system is $10,000.11

A report by researchers at the U.S. Bureau of Mines

showed that the ceramic filter reduced diesel

particulate concentrations by at least 90% on

a load-haul-dump vehicle in a mine.12 No

documentation on the performance of the ceramic

filter specifically for diesel-powered fire trucks was

found in the literature. Engine exhaust filters have

the advantage of removing particulate from the

exhaust stream, but filter only the particulate portion

of the exhaust stream and have relatively high

per-vehicle cost. 

A local exhaust ventilation control for diesel

emissions from a truck’s engine running in the fire

station is the tailpipe exhaust hose (also called an

exhaust extractor). A hose attaches to the tailpipe

and connects to a fan which discharges the diesel

exhaust to the outside. One manufacturer of these

controls recommends an exhaust rate of 600 cubic

feet per minute (cfm) for each vehicle. The hoses

can be purchased with several options. One is an

automatic disconnect feature which automatically

disconnects the hose from the vehicle exhaust pipe as

the vehicle pulls out of the garage. Another option is

to install an overhead rail to keep hoses off of the

floor. The hoses are suspended from the rail by a

balancer that automatically retracts the hose when it

is not in use. Various hose diameters are available

for different size exhaust pipes. Costs will vary with

length of hose, type of overhead mounting, and with

the number of options purchased. 

An advantage of the tailpipe exhaust hose is that it

removes both gaseous and particulate emissions in

the diesel exhaust. The tailpipe exhaust hose

captures the exhaust emissions when the vehicle

exits the fire station but affords no control when the

vehicle reenters the station, unless the exhaust hose is

reattached to the fire truck in the driveway. 

Another control option is to use dilution ventilation.

With dilution ventilation, the air contaminated with

diesel fumes is exhausted to the outside while fresh

outside makeup air flows into the bay through open

doors or supply air openings. Air is exhausted using

a roof or wall fan. The fan can be integrated into the

fire alarm system so that it turns on before the fire

trucks are started. It may also be worthwhile to turn

the fan on for a few minutes after the fire trucks have

returned to the garage. 

The exhaust fan should be located toward the rear of

the apparatus bay opposite the bay doors so that

outside air flows through the open bay doors,

sweeping the entire length of the building before

being exhausted. The exhaust fans should be located

high in the wall or in the ceiling. If the garage doors

cannot be kept open while the exhaust fan is running,

a supply air fan located at the opposite side of the

building from the exhaust fan can be installed to

bring fresh air into the bay. 

The principal advantage of using a dilution

ventilation system is the relatively low initial cost

required. The major drawbacks to using dilution

ventilation are the cost of heating/cooling the

makeup air during times of temperature extremes,
Health Hazard Evaluation Report No. 99-0266-2850 Page 3

and the fact that dilution ventilation does not capture

emissions at the source. 

As the science about the health effects associated

with exposure to diesel exhaust has evolved, so have

the control technologies. The manufacturers of the

different types of controls make claims about their

control’s effectiveness, but a review of the literature

did not identify any objective scientific studies that

have been conducted to evaluate the efficacy of the

control technologies. Accordingly, this study was

conducted to provide an objective evaluation of

ceramic filters for controlling diesel exhaust. 

METHODS

Station Selection

The CMFD is comprised of six fire stations, of

which two were selected for this study. NIOSH

representatives believed, based on recent diesel

exhaust sampling efforts at other fire stations, that to

make a determination as to the effectiveness of the

engineering controls, stations with the highest

potential exposures should be selected for the study.

To determine which stations would be expected to

have the greatest potential diesel exhaust exposures,

NIOSH looked at the following variables: age of the

diesel-powered apparatus operating at each of the

stations, the number of diesel-powered apparatus

operating at each station, and the level of activity

(number of calls) at each station. Based on these

variables for the different CMFD stations, NIOSH

selected two stations in which the potential for diesel

exhaust exposures was greatest. 

Environmental Sampling

Pre- and post-control air sampling was conducted for

diesel exhaust constituents in two fire stations.

Samples were collected to characterize exposures

occurring at the fire stations and to provide data for

determining the effectiveness of the ceramic filters.

During the pre-control evaluation, personal breathing

zone (PBZ) samples and area samples were collected

for Ce, a surrogate measure for whole diesel exhaust.

A minimum of four PBZ samples were collected at

each station during each sampled tour of duty. Area

samples for Ce were collected in the apparatus bay

and living quarters (see Figures 1–4 for sampling

locations). Additionally, area samples were collected

in the apparatus bay for oxides of nitrogen and

VOCs, and grab samples were obtained for SO2.

Three tours were sampled during the three day

sampling effort. In order to evaluate only the

exposure that occurred at the fire stations, rather than

that which occurred while riding in the emergency

vehicles, NIOSH personnel collected sampling

pumps from the employees as they departed from the

station. These pumps were paused until the

employees returned to the station, at which time they

were promptly restarted and given back to the

employees. 

Post-control sampling was conducted on four tours

over a four-day sampling period. This sampling was

limited to area Ce samples collected in the apparatus

bay. This decision was made because PBZ sampling

for Ce and area samples for the gas-phase

constituents yielded very low or none detected

concentrations in the pre-control evaluation.

Air samples for Ce were collected and analyzed in

accordance with NIOSH Method 5040.13 The

samples were collected on quartz-fiber filters in

37-millimeter (mm) diameter cassettes connected via

a length of Tygon® tubing to battery-powered air

sampling pumps operated at a flow rate of 3 liters per

minute (Lpm). PBZ samples and general area

samples were collected over the three days of

sampling. Additionally, one background sample was

collected each day away from sources of diesel

exhaust emissions. Samples obtained after the

ceramic filter installation were collected using the

same methods, but on 25-mm filters because the

smaller filters provide increased sensitivity due to the

reduced volume of solvent needed to extract the

smaller filter. 

Grab samples for SO2 were obtained when a dieselpowered apparatus entered or departed the station.

These measurements were obtained using Sensidyne

5LC colorimetric detector tubes (Sensidyne, Inc.,

Clearwater, Florida). These colorimetric tubes
Page 4 Health Hazard Evaluation Report No. 99-0266-2850

measure SO2 in a concentration range from 0.1 to 25

parts per million (ppm). 

Area air samples for oxides of nitrogen were

collected and analyzed in accordance with NIOSH

method 6014.13 This method utilizes two

triethanolamine (TEA)-treated molecular sieve

sorbent tubes in series, separated by a chromate

oxidizer tube, attached via Tygon tubing to a

battery-powered sampling pump. NO2 is collected

on the first TEA sorbent tube, and is thereby

separated from NO, which is oxidized by the

chromate oxidizer tube and is then collected on the

second TEA sorbent tube. Samples to assess the

time-weighted average exposure to oxides of

nitrogen were collected at a flow rate of 25 milliliters

per minute (mL/min), in the apparatus bay. 

To screen for VOCs, area air samples were collected

using thermal desorption tubes in accordance with

NIOSH method 2459.13 Thermal desorption tubes

contain three sorbent beds in consecutive layers from

front to back (Carbopack Y, Carbopack B, and

Carboxen 1003), which are used to capture organic

compounds over a wide range of volatility.

Substances such as acetone, toluene, pentane, and

hexane will be trapped with this sorbent tube. This

method is an extremely sensitive and a very specific

screening technique; it will identify the compounds

present on the sample in the parts per billion range.

Samples were collected in the apparatus bay,

beginning when the vehicles departed the station in

response to an emergency dispatch, and the pumps

were allowed to run for about two hours. The

thermal desorption tubes were connected via Tygon

tubing to battery-powered sampling pumps operating

at a calibrated flow rate of 50 mL/min. Samples

were analyzed using an automatic thermal desorption

system interfaced directly with a gas chromatograph

and mass selective detector (GC-TD-MSD). Stock

solutions in methanol containing known amounts of

several compounds present in vehicle exhaust were

used to prepare spikes to estimate the concentrations

of solvents collected on the air samples. 

To quantify compounds identified during the

analysis of thermal desorption samples, samples were

collected on charcoal tubes side by side with the

thermal desorption tubes. The charcoal tubes were

placed in plastic holders connected via Tygon tubing

to battery-powered sampling pumps operating at a

flow rate of 200 mL/min. Sampling times matched

those of the thermal desorption tubes. Based upon

the results of the analysis of the thermal desorption

tubes, the charcoal tubes were quantitatively

analyzed for benzene, toluene, and xylene using

NIOSH method 1501.13 

Ventilation Assessment

A qualitative ventilation assessment was conducted

at each fire station to determine the pressure

differentials between the apparatus bay and the living

quarters. The assessment included an overview of

the heating, ventilating, and air-conditioning

(HVAC) system’s modes of operation and a

determination of the operating mode’s effects on

relative pressures between the living quarters and the

bay. Smoke tubes were used to observe relative

pressures through doorways separating the apparatus

bay from the living quarters. 

Statistical Methods

Preliminary determinations of the number of area

samples required to detect a reduction of 50% or

more in concentrations of Ce were made using levels

found in HETA 92-0160-2360, City of Lancaster,

Division of Fire. Power calculations indicated that a

minimum of 26 Ce samples (13 pre-control and 13

post-control samples) would be needed at each fire

station to detect the 50% reduction in levels of

elemental carbon with 90% power and level of

significance of " = 0.050. Subsequent power

calculations using measured pre-control data at Costa

Mesa indicated that 12 samples at each station would

be sufficient. Concentrations in the pre-control data

were found to follow a log-normal distribution, so

logarithms of concentrations were used for all

calculations and statistical tests. 

Several sample concentrations were below the

method limit of detection (LOD). To be included in

statistical analyses, these samples were assigned

values equal to LOD divided by the square root of
Health Hazard Evaluation Report No. 99-0266-2850 Page 5

two.14 All transformations and calculations were

done using the Statistical Analysis System (SAS) v.

8.0, and plots were prepared using S-Plus v. 4.0. 

Plots of concentrations of Ce by numbers of calls per

day were made for each station pre- and postintervention. These are identified as Figures 5 and 6

at the end of the report. 

RESULTS

Pre-Control

Station 3

One 1989 E-One medic engine and one 1989 Quint

were housed in station 3 during this study. The

medic engine was powered by an eight-cylinder

series 92-T Detroit Diesel engine. This engine was

installed in 1998. The Quint was powered by an

eight-cylinder series 92 Detroit Diesel engine, which

was installed in 1994. All diesel engines used No. 2

Diesel Fuel. 

During the sampled period on November 9, the Quint

made two runs and the medic engine made four runs.

On November 10, the Quint made three runs and the

medic engine made five runs. On November 11, the

Quint and the medic engine each made two runs.

Elemental Carbon

Results of Ce sampling in station 3 prior to the

installation of ceramic filters are summarized in

Table 1. A trace Ce concentration was detected on

1 of 12 (8%) PBZ samples collected during the

three-day sampling campaign. No Ce was detected

on the other 11 PBZ samples. Area samples

collected in the apparatus bay ranged from none

detected to 23.5 :g/m3

. These 12 samples had a

geometric mean (GM) of 6.1 :g/m3 (geometric

standard deviation [GSD] of 2.3). A trace

concentration of Ce was detected on seven of thirty

(23%) samples collected in the living quarters of the

fire station. 

Sulfur Dioxide

SO2 was not detected in any grab samples collected

in the apparatus bay. This indicates that the

concentration of SO2 in the bay did not exceed

0.1 ppm as the apparatus entered and departed the

station. 

Nitrogen Oxides

Results of nitrogen oxides sampling in station 3 prior

to the installation of ceramic filters are summarized

in Table 2. Samples collected on November 9 were

not valid and therefore are not reported. Trace

concentrations of NO2 were measured in the bay on

November 10 and 11. This indicated that

concentrations in the bay were less than 0.041 ppm

as an 8-hour TWA. These concentrations were well

below current exposure criteria noted in Table 2.

NO2 measurements were obtained during four-hour

sampling periods. These sampling periods are too

long to permit direct comparison against the shortterm exposure criteria that are established for NO2.

The concentrations do offer a general idea as to the

levels that may have existed during apparatus

departures, if assumptions are made about the timeconcentration pattern. Concentrations during the

four-hour sampling periods ranged from none

detected to trace, indicating that NO2 was detected in

the apparatus bay at an average concentration of less

than 0.27 ppm. These concentrations are averaged

over four-hour sampling periods and suggest that the

1 ppm TLV could have been exceeded when

apparatuses departed the station. 

Volatile Organic Compounds

Results of VOC sampling in station 3 prior to the

installation of ceramic filters are summarized in

Table 3. Low concentrations of several organic

chemicals were identified in the analysis of the

thermal desorption tubes. Identified chemicals

included methyl t-butyl ether, C4–C7 alkanes,

benzene, toluene, and xylenes. Toluene was also

identified on the field blanks. Toluene and xylenes

were present in the greatest abundance.

Accordingly, the charcoal tube samples were

analyzed for toluene and xylenes, and benzene as

well due to its toxicity. Analysis of charcoal tubes
Page 6 Health Hazard Evaluation Report No. 99-0266-2850

recovered undetectable to trace quantities of

benzene, corresponding to airborne concentrations of

less than 0.003 ppm. The concentration of xylenes in

the apparatus bay ranged from undetectable to 0.004

ppm. Field blanks were contaminated with toluene,

which precluded accurate quantitation of toluene

concentrations in the bay. The measured

concentrations of benzene and xylenes were well

below current exposure criteria noted in Table 3. 

Ventilation Assessment

The HVAC system in station 3 supplies air to the

living quarters of the fire station. Air is not

mechanically supplied to the apparatus bay. The

evaluation was made both with the HVAC manually

turned to the “fan on” position, and again with the

fan in the off position. Air consistently moved from

the living quarters and into the bay when the fans

were operating. This condition is ideal for keeping

diesel exhaust from migrating into the living

quarters. When the fans were off, there was slight air

movement from the bay into the living quarters. 

Station 5

A 1997 E-One medic engine and a 1983 Crown

Maxum truck were housed at station 5. The E-One

was powered by a 1997, series 60 six cylinder

Detroit Diesel engine. The truck was powered by a

six cylinder 92 non-computerized Detroit Diesel

engine. 

During the sampled period on November 9, the truck

made four runs and the medic engine made five runs.

On November 10, the truck made one run and the

medic engine made four runs. On November 11, the

truck made one run and the medic engine made two

runs. 

Elemental Carbon

Pre-control Ce sampling results are summarized in

Table 4. Trace concentrations of Ce were detected on

4 of 15 PBZ samples collected during the three-day

sampling campaign, indicating exposures in the

range of 3 to 24 :g/m3

. Area samples collected in the

apparatus bay ranged from none detected to

22.6 :g/m3

. The GM concentration for the 12

samples collected in the apparatus bay was

15.6 :g/m3

 (GSD 1.3). Trace concentrations of Ce

were detected on 10 of 28 samples collected in the

living quarters of the fire station. No Ce was detected

on 18 samples. 

Nitrogen Oxides

Results of nitrogen oxides sampling in station 5 prior

to the installation of ceramic filters are summarized

in Table 5. NO was not detected in three of six

samples collected over the three day period. Three

samples had trace quantities, indicating that NO

concentrations in the bay were less than 0.41 ppm as

an 8-hour TWA. The measured concentrations were

well below current exposure criteria. NO2

measurements were obtained during four-hour

sampling periods. Concentrations during the fourhour sampling periods ranged from none detected to

trace, which equate to concentrations of less than

0.09 ppm to 0.27 ppm in the bay. 

Volatile Organic Compounds

Results of VOC sampling in station 5 prior to the

installation of ceramic filters are summarized in

Table 6. Low concentrations of the same organic

chemicals identified in station 3 were also identified

in samples collected in station 5. Toluene was also

identified on the field blanks. The charcoal tube

samples were analyzed for toluene, xylenes, and

benzene. Analysis of charcoal tubes recovered none

detected to trace quantities of benzene,

corresponding to airborne concentrations of less than

0.003 ppm. The concentration of xylenes in the bay

ranged from 0.004 to 0.009 ppm. Field blanks were

contaminated with toluene, which precluded accurate

quantitation of toluene concentrations in the bay.

Concentrations of benzene and xylene in the bay

were well below current exposure criteria. 

Sulfur Dioxide

SO2 was not detected in any grab samples collected

in the apparatus bay. This indicates that the

concentration of SO2 in the bay did not exceed

0.1 ppm as the apparatus entered and departed the

station. 
Health Hazard Evaluation Report No. 99-0266-2850 Page 7

Ventilation Assessment

As with station 3, the HVAC system in station 5

supplies air to the living quarters of the fire station,

but supplies no air to the apparatus bay. The

evaluation was made with the HVAC manually

turned to the “fan on” position, and again with the

fans in the off position. Air consistently moved from

the bay and into the living quarters when the fans

were in the off position. When the fans were on,

there was slight air movement from the bay into the

living quarters. This is opposite to the more

desirable condition noted at station 3. 

Post-Control

Elemental Carbon

Station 3

During the sampled period on March 14, the Quint

and the medic engine each made four runs. On

March 15, the Quint made one run and the medic

engine made five runs. On March 16, the Quint

made no runs and the medic engine made six runs. 

On March 17, the Quint made no runs and the medic

engine made five runs. See Figure 5 for an

illustration of the number of runs against the Ce

concentration before and after the controls were

installed. 

Post-control Ce sampling results from station 3 are

summarized in Table 8. Trace concentrations of Ce

were detected on 4 of 16 area samples collected in

the bay during the four-day sampling campaign.

Four area samples collected on March 14 had a trace

amount of Ce, indicating that Ce concentrations in the

bay ranged from 1.3 to 5.1 :g/m3

. The 16 samples

had a GM Ce concentration of 1.5 :g/m3

. Geometric

mean Ce concentrations were reduced by 76% from

pre-control levels. 

Station 5

During the sampled period on March 14, the truck

and medic engine each made three runs. On

March 15, the truck made three runs and the medic

engine made four runs. On March 16, the truck

made no runs and the medic engine made three runs.

On March 17, the truck made no runs and the medic

engine made four runs. See Figure 6 for an

illustration of the number of runs against the Ce

concentration before and after the controls were

installed. 

Post-control Ce sampling results from station 5 are

summarized in Table 9. Trace Ce was detected on

5 of 16 area samples collected during the four-day

sampling campaign. Ce was detected in two area

samples collected on March 15, and in three area

samples collected on March 17, indicating that Ce

concentrations for these samples ranged from 1.3 to

5.1 :g/m3

. The 16 samples had a GM Ce

concentration of 1.4 :g/m3. Geometric mean Ce

concentrations were reduced by 91% from precontrol levels. 

DISCUSSION

In the two stations, which were deemed a priori to

have the greatest potential diesel exhaust exposure,

personal Ce exposures were low. Two factors likely

played a role in keeping these PBZ exposures low.

First, Ce concentrations measured in the apparatus

bay of each station were moderate compared to

concentrations that have been measured in other

settings.15,16,17 Second, fire fighters and paramedics

spent very little time in the apparatus bay. Summary

results of the PBZ samples are reported in Tables 10

and 11 for stations 3 and 5, respectively. The

post-control area sample results are presented in

Tables 12 and 13. 

The low concentrations of gas-phase constituents

measured at the CMFD stations are consistent with

the findings of previous NIOSH evaluations of diesel

exhaust.15,16,17 These findings suggest that gas-phase

components would not approach the evaluation

criteria, with the exception of NO2 in extreme

exposure scenarios. Through previous research and

field studies of diesel exhaust, it has been

documented that, although CO is generated, the

levels generated are notably less than those generated

by gasoline engines.18,19 The small amounts of CO
Page 8 Health Hazard Evaluation Report No. 99-0266-2850

generated by diesel engines have not been found to

create a significant CO hazard in open spaces such as

an apparatus bay. For this reason, CO was not

measured in this study. 

In addition to the previously noted factors (i.e., age

and number of engines, level of activity, size of

station) that may affect diesel exhaust exposures in

fire stations, an additional factor was noted during

this study that should be considered when

referencing the findings of this study as a basis for

decision making with regard to installing ceramic

filter controls at other fire stations. Both of the

stations studied had pull-through apparatus bays.

Apparatus movement in and out of a fire station bay

generally occurs in one of two ways. For bays

having doors at the front and the back, apparatus may

pull out through the front doors when departing the

station and pull forward through the back doors

when returning. In contrast, a station having doors

only at the front of the bay would require the

apparatus to stop and back into the bay. Since

pulling forward through the bay is a decelerating

action, it typically requires little or no effort from the

engine. In fact, some of the CMFD engineers shut

off the engine and coasted into the bay. Backing into

the bay typically requires the engineer to stop in the

street or driveway and accelerate the engine through

the threshold of the bay. This acceleration would be

expected to generate more exhaust than would

deceleration. 

The ceramic diesel exhaust filtration system installed

at the CMFD included a switch in the cab, which

allowed the engineer to override the system. At

station 3 on March 14, the NIOSH industrial

hygienists found the exhaust diverter switch in the

off position. The engineer on the apparatus routinely

turns all switches off at the end of each run.

Consequently, the switch for the diesel exhaust

control had been inadvertently disengaged. The

switch had remained in the off position during the

second run. The engineer was consulted and

indicated that he would leave the exhaust control

switch on. This may have contributed to the small

amount of Ce that was measured in the station 3 bay

on March 14. More importantly though, this episode

points out the need for information about the new

engineering control and its operation be provided to

fire department personnel at the time of installation.

Reportedly, this information was casually passed

along by word of mouth from tour to tour. 

CONCLUSIONS

The NIOSH environmental assessment of diesel

exhaust in two CMFD fire stations found that

concentrations of gas-phase components of diesel

exhaust were well below their respective evaluation

criteria prior to the installation of engineering

controls. Personal exposures to diesel exhaust

particulates in these two fire stations were also low

because the quantities of Ce generated were moderate

and because firefighters and paramedics did not

spend much time in the apparatus bay.

Concentrations of diesel soot (measured as Ce) in the

bays were reduced by 76% and 91% in stations 3 and

5, respectively, after the ceramic diesel exhaust

filters were installed. NIOSH researchers conclude

that, in stations with pull-through apparatus bays, the

ceramic filters are effective at reducing the emission

of diesel soot into the apparatus bay. Further study is

needed to determine the effectiveness of this and

other controls for reducing diesel exhaust at stations

where the apparatuses are required to back into the

station. Although this study suggested that gas-phase

components of diesel exhaust do not build up to

unhealthful levels in closed apparatus bays without

the filter controls, additional study may be warranted

to determine the effectiveness of this and other

engineering controls at limiting gas-phase

components from environments where they may

accumulate. 

RECOMMENDATIONS

The following recommendations are offered to

further minimize the potential for diesel exhaust at

the CMFD: 

1. When ceramic filters or other engineering controls

are installed in fire apparatus at other stations, it is

recommended that a more formalized means of
Health Hazard Evaluation Report No. 99-0266-2850 Page 9

1. Linell RH, Scott WE [1962]. Diesel exhaust

composition and odor studies. J Air Pollut

Control Assoc 12:510–545.

2. Environmental Health Associates, Inc.

[1978]. Health effects of diesel exhaust emissions.

Berkeley, CA: Environmental Health Associates,

Inc.

3. Schenker [1980]. Diesel exhaust––an

occupational carcinogen? J Occup Med 22:41–46.

4. Travis CC, Munro NB [1983]. Potential

health effects of light-duty diesel exhaust. Risk

Analysis 3:147–155.

5. NIOSH [1988]. Current intelligence bulletin

50: Carcinogenic effects of exposure to diesel

exhaust. Cincinnati, OH: U.S. Department of

Health and Human Services, Public Health

Service, Centers for Disease Control, National

Institute for Occupational Safety and Health,

DHHS (NIOSH) Publication No. 88-116. 

6. Weisenberger [1984]. Health effects of diesel

emissions––an update. J Soc Occup Med

34:90–92.

7. Cuddihy RG, Griffith WC, McClellan RO

[1984]. Health risks from light-duty diesel

vehicles. Environ Sci Technol 18:14A–21A.

8. Froines JR, Hinds WC, Duffy RM [1987].

Exposure of fire fighters to diesel emissions in fire

stations. Am Ind Hyg Assoc 48(3)202–207.

9. Garshick E, Schenker MB, Munoz A,

Segal M [1988]. A retrospective cohort study of

lung cancer and diesel exposure in railroad

workers. Am Rev Resp Dis 137:820–825.

10. ACGIH [2001]. 2001 TLVs® and BEIs®:

Threshold limit values for chemical substances

and physical agents & biological exposure indices.

Cincinnati, OH: American Conference of

Governmental Industrial Hygienists.

11. Ward Diesel Filter Systems, Inc. No smoke

exhaust filtration. Elmira Heights, New York.

12. Baumgard KJ [1986]. Estimation of diesel

particulate matter reductions in underground

mines resulting from the use of a ceramic particle

trap. Annals of the American Conference of

Governmental Industrial Hygienists 14:257–263.

13. NIOSH [1998] NIOSH manual of analytical

methods. Vol. 4. Cincinnati, OH: U.S. Department

of Health and Human Services, Public Health

Service, Centers for Disease Control and

Prevention, National Institute for Occupational

Safety and Health. DHHS (NIOSH) Publication

No. 98-119.

14. Hornung RW, Reed LD [1990]. Estimation

of average concentration in the presence of

nondetectable values. Appl Occup Environ Hyg

5:46–51.

15. NIOSH [1993]. City of Lancaster Firehouse,

Lancaster, OH. Cincinnati, OH: U.S. Department

of Health and Human Services, Public Health

Service, Centers for Disease Control and

Prevention, National Institute for Occupational

Safety and Health, NIOSH HETA Report No.

92-0160-2360. 

training be established to communicate information

about the control to CMFD personnel. 

2. In station 5, the NIOSH industrial hygienist

observed that air moves from the apparatus bay into

the living quarters when the HVAC system is not

circulating air. The cause for this was not identified

at the time of the survey. One explanation is that the

exhaust vents in the kitchen and bathrooms may be

moving enough air from the living quarters to create

low pressure relative to the apparatus bay. The ideal

relationship for keeping diesel exhaust out of the

living quarters, as observed in station 3, is for air to

move from the living quarters into the bay. It is

recommended that the air flow from the bathroom

and kitchen exhaust fans and the air supply fans be

balanced to minimize the migration of diesel exhaust

into the living quarters. 

REFERENCES
Page 10 Health Hazard Evaluation Report No. 99-0266-2850

16. NIOSH [1998]. Racine Fire Department,

Racine, WI. Cincinnati, OH: U.S. Department of

Health and Human Services, Public Health

Service, Centers for Disease Control and

Prevention, National Institute for Occupational

Safety and Health, NIOSH HETA Report No.

97-0304-2695.

17. NIOSH [1999]. San Francisco Municipal

Railway, Flynn Facility, San Francisco, CA.

Cincinnati, OH: U.S. Department of Health and

Human Services, Public Health Service, Centers

for Disease Control and Prevention, National

Institute for Occupational Safety and Health,

NIOSH HETA Report No. 98-0041-2741.

18. Bureau of Mines [1973] Hazards from

engines rebreathing exhaust in confined spaces.

Publications Distribution Branch. Bureau of

Mines. Report of investigation number 7757. 

19. Waller RE, Commins BT, Lawther PJ [1961].

Air pollution in road tunnels. Brit. J. of Ind. Med.

18:250–259.

Table 1. Results of air sampling for elemental carbon at fire station 3 prior to the installation of ceramic

filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Area Sample Location or

Job Title

Sample Time

(minutes)

Concentration in air

(:g/m3

)

Personal Breathing Zone Samples

November 9

Living quarters/apparatus Engineer 267 ND1

Living quarters/apparatus Engineer 391 ND

Living quarters/apparatus Firefighter/paramedic 389 ND

Living quarters/apparatus Firefighter/paramedic 235 ND

Living quarters/apparatus Captain 368 ND

November 10

Living quarters/apparatus Engineer 365 ND

Living quarters/apparatus Firefighter/paramedic 367 ND

Living quarters/apparatus Captain 363 ND
Health Hazard Evaluation Report No. 99-0266-2850 Page 11 November 11

Living quarters/apparatus Engineer 246 ND

Living quarters/apparatus Engineer 267 ND

Living quarters/apparatus Firefighter/paramedic 192 14.8t2

Living quarters/apparatus Firefighter/paramedic 225 ND

General Area Air Samples

November 9

Apparatus Bay Center 482 4.1t

Apparatus Bay Rear center 481 ND

Apparatus Bay Generator door 471 4.8t

Apparatus Bay North wall ladder 481 ND

Dining room on table 487 ND

Dormitory on locker 19 484 ND

Dormitory on locker 13 482 ND
Page 12 Health Hazard Evaluation Report No. 99-0266-2850

Dormitory on locker 10 494 ND

Kitchen on television 484 ND

Kitchen on refrigerator 485 ND

Dormitory on locker 26 487 ND

Library on bookcase 485 ND

Office on desk by window 486 ND

Office on table by portraits 487 ND

Outside Fence line 479 ND

November 10

Apparatus Bay Center 481 23.5

Apparatus Bay Rear center 485 23.1

Apparatus Bay Generator door 482 20.7

Apparatus Bay North wall ladder 484 20.8

Dining room on table 484 3.0t

Dormitory on locker 19 478 ND

Dormitory on locker 13 483 ND

Dormitory on locker 10 486 ND

Kitchen on television 506 ND

Kitchen on refrigerator 487 3.2t

Dormitory on locker 26 487 ND

Library on bookcase 486 4.1t

Office on desk by window 486 ND

Office on table by portraits 480 3.0t

Outside Fence line 483 ND

November 11

Apparatus Bay Center 478 6.0t

Apparatus Bay Rear center 477 ND

Apparatus Bay Generator door 473 8.0t

Apparatus Bay North wall ladder 478 6.0t
Health Hazard Evaluation Report No. 99-0266-2850 Page 13

Dining room on table 479 ND

Dormitory on locker 19 478 ND

Dormitory on locker 13 479 ND

Dormitory on locker 26 478 ND

Dormitory on locker 10 487 3.2t

Kitchen on television 479 ND

Kitchen on refrigerator 479 3.6t

Library on bookcase 480 ND

Office on desk by window 478 3.6t

Office on table by portraits 480 3.0t

Outside Fence line 477 4.8t

1

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for this sample set

was 0.5 micrograms (:g) of Ce per sample. Due to the relatively small sample volumes, the minimum detectable

concentrations (MDC) for the subset of PBZ samples ranged from 11 to 19 :g/m3

. For area samples the MDC was

3 :g/m3

. 2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative. 
Page 14 Health Hazard Evaluation Report No. 99-0266-2850

Table 2. Results of air sampling in the apparatus bay for oxides of nitrogen at fire station 3 before the

installation of ceramic filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Sample Location Sample Time1 Concentration in air (ppm)

Nitrogen Dioxide Nitric Oxide 

General Area Air Samples November 9

Center of Bay

--samples not valid--

North wall ladder

--samples not valid--

November 10

Center of Bay

0829-1332 .18t2 .28t

.14t4

1338-1616 ND3 ND

North wall ladder

0828-1339 .27t .28t

.14t

1346-1616 ND ND

November 11

Center of Bay

0741-1128 .09t .14t

.07t

1128-1540 ND ND

North wall ladder

0742-1130 .09t .14t

.07t

1130-1537 .09t ND

OSHA PEL 25

NIOSH REL 25

1

 Times are reported in military time.

2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.

3

 “ND” means none of the analyte was detected in this sample. The limit of detection for this sample set is 0.8

:g/sample. 

4

 Values in this column are 8-hour time weighted averages (TWAs).
Health Hazard Evaluation Report No. 99-0266-2850 Page 15

Table 3. Results of air sampling for volatile organic compounds at fire station 3 before the installation of

ceramic filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Sample Location Sample Time (min.)

Concentration in air (ppm)

Benzene Xylenes

General Area Air Samples

November 9

Center of Bay 474 ND1 ND

North wall ladder 464 ND ND

November 10

Center of Bay 477 ND .004

North wall ladder 477 ND .002t2

November 11

Center of Bay 481 .002t .004

North wall ladder 480 .002t .004

OSHA PEL 1 100

NIOSH REL 0.1 100

1

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for benzene and

xylenes was 0.4:g/sample, corresponding to MDCs of 0.001 ppm. 2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.
Page 16 Health Hazard Evaluation Report No. 99-0266-2850

Table 4. Results of air sampling for elemental carbon at fire station 5 prior to the installation of ceramic

filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Area Sample Location or

Job Title

Sample Time

(min.)

Concentration in air

(:g/m3

)

Personal Breathing Zone Samples

November 9

Living quarters/ apparatus Engineer 213 ND1

Living quarters/ apparatus Engineer 237 7.1t2

Living quarters/ apparatus Firefighter/Paramedic 267 ND

Living quarters/ apparatus Firefighter/Paramedic 232 ND

Living quarters/ apparatus Firefighter/Paramedic 232 ND

Living quarters/ apparatus Captain 274 ND

November 10

Living quarters/ apparatus Engineer 273 ND

Living quarters/ apparatus Firefighter/Paramedic 290 5.9t

Living quarters/ apparatus Firefighter/Paramedic 273 ND

Living quarters/ apparatus Captain 273 ND

November 11

Living quarters/ apparatus Engineer 361 ND

Living quarters/ apparatus Firefighter/Paramedic 467 4.3t

Living quarters/ apparatus Firefighter/Paramedic 361 5.4t

Living quarters/ apparatus Captain 363 ND

Living quarters/ apparatus Tillerman 365 ND

General Area Air Samples

November 9

Apparatus Bay Center 493 22.6

Apparatus Bay NE ladder 471 21.4

Apparatus Bay SE ladder 473 10.8t

Apparatus Bay SW ladder 484 18.7
Health Hazard Evaluation Report No. 99-0266-2850 Page 17

Dining room on table 487 ND

East Dormitory on window sill 474 ND

East Dormitory on locker 29 474 ND

West Dormitory on window sill 475 ND

West Dormitory on locker 18 474 ND

Kitchen on counter 486 ND

Kitchen on refrigerator 490 ND

Television room on table 476 ND

Office on window sill 493 3.1t

Office on filing cabinet 493 3.0t

Outside on fence 471 ND

November 10

Apparatus Bay Center 477 18.6

Apparatus Bay NE ladder 481 15.7

Apparatus Bay SE ladder 483 13.3

Apparatus Bay SW ladder 482 14.1

Dining room on table 446 3.4t

East Dormitory on window sill 478 ND

East Dormitory on locker 29 478 ND

West Dormitory on window sill 475 ND

West Dormitory on locker 18 474 ND

Kitchen on counter 480 3.8t

Kitchen on refrigerator 307 ND

Television room on table 435 ND

Office on window sill 480 ND

Office on filing cabinet 480 3.5t

Outside on fence 466 ND

November 11

Apparatus Bay Center 486 13.9

Apparatus Bay NE ladder 486 17.3

Apparatus Bay SE ladder 496 14.3
Page 18 Health Hazard Evaluation Report No. 99-0266-2850

Apparatus Bay SW ladder 496 11.5t

Dining room on table 486 ND

East Dormitory on window sill 481 3.0t

East Dormitory on locker 29 481 ND

West Dormitory on window sill 486 ND

West Dormitory on locker 18 486 2.9t

Kitchen on counter 490 ND

Television room on table 482 ND

Office on window sill 465 3.1t

Office on filing cabinet 465 3.7t

Outside on fence 479 ND

1

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for this sample set

was 0.5 micrograms (:g) of Ce per sample. Due to the relatively small sample volumes, the MDCs for the subset

of PBZ samples ranged from 11 to 19 :g/m3

. For area samples the MDC was 3 :g/m3. 2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.
Health Hazard Evaluation Report No. 99-0266-2850 Page 19

Table 5. Results of air sampling in the apparatus bay for oxides of nitrogen at fire station 5 before the

installation of ceramic filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Sample Location Sample Time1 Concentration in air (ppm)

Nitrogen Dioxide Nitric Oxide 

General Area Air Samples

November 9

Center of Bay

0840-1239 ND2 .12t3

.13t4

1239-1640 .09t .14t

NE ladder

0842-1235 ND ND

ND

1235-1638 ND ND

November 10

Center of Bay

0738-1138 .09t .28t

.20t

1138-1540 .09t .12t

NE ladder

0739-1142 ND ND

ND

1142-1541 ND ND

November 11

Center of Bay

0743-1227 ND ND

ND

1227-1553 ND ND

NE ladder

0743-1227 .18t .28t

.14t

1227-1553 .09t ND

OSHA PEL 25

NIOSH REL 25

1

 Times are reported in military time.

2

 “ND” means none of the analyte was detected in this sample. The limit of detection for this sample set is 0.8

:g/sample.

3

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.

4

 Values in this column are 8-hour time weighted averages (TWAs).
Page 20 Health Hazard Evaluation Report No. 99-0266-2850

Table 6. Results of air sampling for volatile organic compounds at fire station 5 before the installation of

ceramic filter controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Sample Location Sample Time (min.)

Concentration in air (ppm)

Benzene Xylenes

General Area Air Samples

November 9

Center of Bay 481 ND1 .004

NE ladder 476 ND .005

November 10

Center of Bay 481 ND .004

NE ladder 482 ND .004

November 11

Center of Bay 486 .003t2 .009

NE ladder 488 .003t .009

OSHA PEL 1 100

NIOSH REL 0.1 100

1

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for benzene and

xylenes was 0.4:g/sample, corresponding to MDCs of 0.001 ppm. 2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.
Health Hazard Evaluation Report No. 99-0266-2850 Page 21

Table 7. Results of air sampling for sulfur dioxide at fire station 5 before the installation of ceramic filter

controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Sample Location Time of Collection1 Concentration in air (ppm)

November 9

Apparatus Bay 0930 ND2

Apparatus Bay 1007 ND

Apparatus Bay 1144 ND

Apparatus Bay 1310 ND

Apparatus Bay 1408 ND

Apparatus Bay 1504 ND

Apparatus Bay 1547 ND

Apparatus Bay 1606 ND

1

 Times are reported in military time.

2

 “ND” means none of the analyte was detected in the sample, indicating that SO2 concentrations were less than

0.1 ppm. 
Page 22 Health Hazard Evaluation Report No. 99-0266-2850

Table 8. Results of air sampling for elemental carbon at fire station 3 after the installation of ceramic filter

controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Area Sample Location or

Job Title Sample Time Concentration in air

(:g/m3

)

General Area Air Samples

March 14

Apparatus Bay Center 484 1.8t1

Apparatus Bay Rear center 484 2.6t

Apparatus Bay Generator door 483 2.8t

Apparatus Bay North wall ladder 484 1.9t

Outside Fence line 484 ND2

March 15

Apparatus Bay Center 478 ND

Apparatus Bay Rear center 477 ND

Apparatus Bay Generator door 478 ND

Apparatus Bay North wall ladder 478 ND

Outside Fence line 475 ND

March 16

Apparatus Bay Center 480 ND

Apparatus Bay Rear center 480 ND

Apparatus Bay Generator door 480 ND

Apparatus Bay North wall ladder 480 ND

Outside Fence line 480 ND

March 17

Apparatus Bay Center 480 ND

Apparatus Bay Rear center 480 ND

Apparatus Bay Generator door 480 ND

Apparatus Bay North wall ladder 480 ND

Outside Fence line 479 ND

1

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.

2

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for this sample set

was 0.5 micrograms (:g) of Ce per sample. The MDC for this sample set was 1.3 :g/m3

.
Health Hazard Evaluation Report No. 99-0266-2850 Page 23

Table 9. Results of air sampling for elemental carbon at fire station 5 after the installation of ceramic filter

controls. Costa Mesa Fire Department. (HETA 99-0266) Date

Area Sample Location or

Job Title Sample Time Concentration in air

(:g/m3

)

General Area Air Samples

March 14

Apparatus Bay Center 496 ND1

Apparatus Bay NE ladder 498 ND

Apparatus Bay SE ladder 492 ND

Apparatus Bay SW ladder 495 ND

Outside On fence 489 ND

March 15

Apparatus Bay Center 495 ND

Apparatus Bay NE ladder 498 2.0t2

Apparatus Bay SE ladder 494 2.3t

Apparatus Bay SW ladder 482 ND

Outside On fence 499 ND

March 16

Apparatus Bay Center 484 ND

Apparatus Bay NE ladder 485 ND

Apparatus Bay SE ladder 485 ND

Apparatus Bay SW ladder 482 ND

Outside On fence 485 ND

March 17

Apparatus Bay Center 495 ND

Apparatus Bay NE ladder 492 1.5t

Apparatus Bay SE ladder 493 1.2t

Apparatus Bay SW ladder 492 1.7t

Outside On fence 492 ND

1

 “ND” means none of the analyte was detected in this sample. The analytical limit of detection for this sample set

was 0.5 micrograms (:g) of Ce per sample. The MDC for this sample set was 1.3 :g/m3

. 2

 A “t” next to the value indicates that the analyte was detected at trace concentrations. Concentrations in the trace

range are semi-quantitative.
Page 24 Health Hazard Evaluation Report No. 99-0266-2850

Table 10. Descriptive statistics of PBZ and area elemental carbon concentrations before control, by location

at fire station 3. Nondetectable values replaced by LOD. Costa Mesa Fire Department. (HETA 99-0266)

Location/Job N= Arithmetic

 Mean

Arithmetic

Standard

Deviation

Geometric

 Mean

Geometric

Standard

Deviation

Captain 2 3.9203 0.10140 3.9197 1.02620

bay 12 8.7583 8.41356 6.0656 2.34047

engine 1 5.8134 5.8134

Engineer 2 4.6286 0.85388 4.5891 1.20386

FF 3 8.2568 5.80592 7.0361 1.98043

FF/Paramedic 1 3.6511 3.6511

in rig 1 10.5290 10.5290

living quarters 30 3.6887 3.25178 3.2852 1.43632

Med Engineer 1 5.3371 5.3371

outside 2 2.9726 0.03154 2.9725 1.01067

Paramedic/FF On 2 5.5683 1.08189 5.5155 1.21596

Quint Engineer 1 5.7927 5.7927
Health Hazard Evaluation Report No. 99-0266-2850 Page 25

Table 11. Descriptive statistics of PBZ and area elemental carbon concentrations before control, by location

at fire station 5. Nondetectable values replaced by LOD. Costa Mesa Fire Department. (HETA 99-0266)

Location/Job N= Arithmetic

 Mean

Arithmetic

Standard

Deviation

Geometric

 Mean

Geometric

Standard

Deviation

bay 12 16.0135 3.74960 15.6187 1.26297

Captain on truck 3 4.7820 0.74175 4.7411 1.17758

Engineer 1 5.2198 5.2198

Engineer on engine 1 7.1438 7.1438

Engineer on truck 2 5.3188 1.93943 5.1389 1.45217

FF on engine 1 5.4003 5.4003

FF on truck 1 5.3317 5.3317

FF/Medic on engine 2 5.5582 0.47855 5.5479 1.09003

FF/Medic on truck 2 6.1422 0.00000 6.1422 1.00000

FF/Paramedic 1 4.2719 4.2719

living quarters 29 3.1374 0.36711 3.1200 1.10820

outside 3 2.9895 0.01676 2.9894 1.00562

Truck Tillerman 1 3.9041 3.9041
Page 26 Health Hazard Evaluation Report No. 99-0266-2850

Table 12. Descriptive statistics of area elemental carbon concentrations after control, by location at fire

station 3. Nondetectable values replaced by LOD. Costa Mesa Fire Department. (HETA 99-0266) 

Location/Job N= Arithmetic

 Mean

Arithmetic

Standard

Deviation

Geometric

 Mean

Geometric

Standard

Deviation

bay 16 1.49980 0.42286 1.45554 1.27028

outside 4 1.27234 0.01038 1.27231 1.00822

Table 13. Descriptive statistics of area elemental carbon concentrations after control, by location at fire

station 5. Nondetectable values replaced by LOD. Costa Mesa Fire Department. (HETA 99-0266)

Location/Job N= Arithmetic

 Mean

Arithmetic

Standard

Deviation

Geometric

 Mean

Geometric

Standard

Deviation

bay 16 1.43196 0.32426 1.40431 1.21359

outside 4 1.28243 0.03008 1.28217 1.02378

 
Health Hazard Evaluation Report No. 99-0266-2850 Page 27

X

Medic Engine 83

Quint 83

X Apparatus Bay

kitchen

Dining Room

Office

X Library Capt. Dorm

X

X

 X

X

X

X

X

Figure 1. Ground floor of fire station 3. Pre-control elemental carbon sampling locations are indicated

with an X.
Page 28 Health Hazard Evaluation Report No. 99-0266-2850

Apparatus Bay

 W. Dorm

 E. Dorm

 Bathroom

X

X

X

X

Figure 2. Second floor of fire station 3. Pre-control elemental carbon sampling locations are indicated

with an X.
Health Hazard Evaluation Report No. 99-0266-2850 Page 29

 Apparatus Bay

Dining Rom

 Kitchen

Capt. Dorm

 B.C. Dorm

 Television Room

Office

X

X

X

X

X

 Patio

X

X

X

X

 X

 

Figure 3. Ground floor of fire station 5. Pre-control elemental carbon sampling locations are indicated

with an X.
Page 30 Health Hazard Evaluation Report No. 99-0266-2850

 Apparatus Bay

Library

East Dorm

West Dorm

X

X

X

X

Figure 4. Second floor of fire station 5. Pre-control elemental carbon sampling locations are indicated

with an X.
Health Hazard Evaluation Report No. 99-0266-2850 Page 31

0 1 2 3 4 5 6 7 8 9 10

N um ber of C alls

0

5

1 0

1 5

2 0

2 5

3 0

Concentration (ug/m3)

P ost-C ontrol

P re-control

0 1 2 3 4 5 6 7 8 910

Number of Calls

0

5

10

15

20

25

30

Concentration (ug/m3)

Post-Control

Pre-control

Plot of Ce concentrations measured in bay vs. number of calls.

Costa Mesa Fire Department. (HETA 99-0266)

Figure 5. Comparison of pre- and post-control concentrations, fire station 3.

Figure 6. Comparison of pre- and post-control concentrations, fire station 5.
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