United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General

Technical Report

PNW-GTR-448

March 1999

Guide to Monitoring

Smoke Exposure of

Wildland Firefighters

Tim E. Reinhardt, Roger D. Ottmar, and Michael J. Hallett
TIM E. REINHARDT is an industrial hygienist, Radian International LLC, 11711 S.E.

Eighth Street, Suite 200, Bellevue, WA 98005; and ROGER D. OTTMAR is a research

forester and MICHAEL J. HALLETT is a physical science technician, U.S. Department

of Agriculture, Forest Service, Pacific Northwest Research Station, Forestry Sciences

Laboratory, 4043 Roosevelt Way NE, Seattle WA 98105.

Authors
Abstract

Contents

Reinhardt, Tim E.; Ottmar, Roger D.; Hallett, Michael J. 1999. Guide to monitoring

smoke exposure of wildland firefighters. Gen. Tech. Rep. PNW-GTR-448. Portland,

OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research

Station. 15 p.

Fire managers and safety officers concerned with smoke exposure among fire 

crews can use electronic carbon monoxide (CO) monitors to track and prevent 

overexposure to smoke. Commonly referred to as dosimeters, these lightweight instruments measure the concentration of CO in the air the firefighter’s breathe. This guide

outlines the protocol developed for sampling smoke exposure among firefighters with

CO dosimeters. It provides a basic template for managers and safety officers interested in establishing their own smoke-exposure monitoring program.

Keywords: Fire, smoke, human health, occupational exposure, safety, smoke 

exposure.

1 Introduction

1 Objective of Measuring Carbon Monoxide

2 Electronic Dosimeter Capabilities

5 Basic Equipment

5 Suggested Protocol

7 Calibration

8 Alarm Adjustment

9 Quality-Control Check

10 Monitoring

12 Carbon Monoxide and Other Smoke Hazards

14 Conclusion

15 Literature Cited

15 Appendix
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Document continues on next page.
Objective of

Measuring

Carbon Monoxide

Fire managers and safety officers concerned with smoke exposure among their fire

crews can use electronic carbon monoxide (CO) monitors to track and prevent over

exposure to smoke. Commonly referred to as dosimeters, these lightweight instruments measure the concentration of CO in the air that firefighters breathe. The

electronic dosimeter continuously senses the amount of CO in the air it encounters,

and when the dosimeter is near the firefighter’s face, it measures the CO that the firefighter is exposed to during the workday. Unlike passive sorbent tube dosimeters that

indicate CO exposure via a color change, the electronic dosimeter contains electronic

circuitry to measure and automatically indicate unsafe levels of CO. Electronic CO

dosimeters are versatile, economical tools that can give fire managers instant data

about the safety of their crews’ working conditions. Advanced models also can record

and transfer the data to a computer for a permanent record.

For the past 5 years, the USDA Forest Service, Pacific Northwest Research Station

(PNW) in Seattle, Washington, has conducted studies on smoke exposure among

wildland firefighters (fig. 1). Through the course of this work, comparisons between CO

dosimeter results and traditional CO-exposure sampling methods have proven dosimeters to be accurate and precise, giving minute-by-minute updates of current smoke

conditions. Although there are several other hazardous substances in smoke that are

difficult and costly to monitor, they are sufficiently correlated with CO to allow measurements of CO exposure to be used to estimate exposure to these additional

hazards. This guide outlines the protocol developed at PNW for sampling smoke exposure among firefighters with CO dosimeters. It provides a basic template for 

managers and safety officers interested in establishing their own smoke-exposure

monitoring programs.

Carbon monoxide is a toxic gas and is a common byproduct of incomplete combustion. Dense smoke produced from a wildfire has high concentrations of CO, similar

to the exhaust from an automobile engine. The Occupational Safety and Health

Administration (OSHA) regulates workplace CO exposure to prevent occupational

illnesses. Because CO has no color, odor, or taste, it can be dangerous to firefighters

at wildfires and prescribed burns. Although firefighters are usually exposed to less CO

than city dwellers, occasionally they encounter higher concentrations on the fireline.

Recent measurements of CO exposure among firefighters at both wildfires and 

prescribed burns have shown that exposure to CO can exceed recommended 

occupational exposure limits between 1 and 5 percent of the time (Reinhardt and

others 1994b). When this occurs, firefighters may have the following symptoms:

• Reduced work capacity

• Loss of time awareness

• Decreased vigilance

• Difficulty with decisionmaking

• Difficulty performing complex tasks

• Headache

• Dizziness

• Nausea

1

Introduction
The consequences of these symptoms can be serious at a wildfire or prescribed burn,

where the safety of many people may depend on the actions of someone affected by

CO exposure. The symptoms disappear after a few hours in a CO-free environment,

but if exposure to high CO levels is sustained, the effects can be more harmful.

Firefighters with angina or cardiovascular disease, or those who are pregnant, have an

increased risk of adverse health effects from CO exposure. Smokers also may be susceptible to adverse effects from occupational CO exposure because they are already

exposed to CO from cigarettes.

There is no suitable respirator currently available to protect firefighters from CO exposure. Organizations that manage wildland fire must accomplish their primary mission;

yet their concern about the health of their employees and their legal obligation to provide a safe work environment may conflict with effective fire management. Routine CO

monitoring can help to achieve both these goals.

There are three basic types of electronic dosimeters. Fundamental differences in their

capabilities make the selection of the appropriate dosimeter important. The three types

are as follows:

• Monitors that simply measure ambient CO levels continuously and alarm when the

CO level goes above a preset limit. The Mine Safety Appliance Corporation (MSA)

CricketTM and Industrial Scientific Corporation (ISC) GasBadgeTM are two examples

of these low-cost devices.1

2

Electronic

Dosimeter

Capabilities

1 The use of trade or firm names in this publication is for reader

information and does not imply endorsement by the U.S.

Department of Agriculture of any product or service.

Figure 1—Pike hotshot crew members being sampled for smoke exposure during the County Line Fire.
• Dosimeters that (1) continuously measure the CO concentration, (2) have alarm

capabilities, and (3) calculate an average work shift exposure for comparison with

work shift exposure limits. The Draeger® Model 190 dosimeter, MSA MiniCoTM, and

ISC STX70 display version are examples of these useful dosimeters.

• Datalogging dosimeters (dataloggers) that not only measure and display the ambient and work shift average CO concentrations but also store the data for later

analysis on a computer. The Draeger Model 190 datalogger, ISC STX70 datalogging

monitor, and the MSA MicroMACTM personal alarm are examples of dataloggers.

Dosimeters differ in cost and size—some are smaller than a pack of cigarettes. Display

and nondisplay versions are available. All models are equipped with an alarm to alert

the user when the CO concentration reaches a specific level. Ruggedness, water

resistance, ambient temperature limits, and shielding from radio frequency interference are important features to consider when purchasing a dosimeter. (Three

manufacturers are listed in the appendix.)

The inexpensive nondisplay dosimeter is useful because it instantly alerts the user

when ambient CO concentrations reach the alarm level. No interpretation of numbers

is necessary. Although effective at warning users during peak exposure situations

exceeding a 200-parts-per-million (ppm) CO ceiling limit, the least sophisticated 

models are not as effective when CO levels are moderate but variable during the 

work shift.

As an example, firefighters often will encounter CO levels that rise and fall but usually

remain below the ceiling limit. The time-weighted average (TWA) exposure is the

important measurement for work shifts during which the ceiling limit is not exceeded.

Think of this as an average exposure over the work shift—the “weighting” is a simple

formula, important only when the average is based on two or more samples of

unequal duration. Depending on the health and safety agency with jurisdiction over the

organization (that is, OSHA or an equivalent state agency), the permissible exposure

limit (PEL) or threshold limit value (TLV) are the criteria against which the TWA exposure is compared (we recommend a TLV of 25 ppm CO and a ceiling limit of 200 

ppm CO).

The TWA is calculated and displayed by the latter two types of dosimeters. As long 

as the TWA exposure limit is not exceeded, firefighters may continue to work without

concern, because periods when CO is above the limit are compensated for by periods

when CO is below the limit. When the TWA exposure limit is exceeded, further CO

exposure above the limit is unsafe for that work shift. For example, if a crew had 

accumulated a 25-ppm TWA exposure after the first 4 hours of their 8-hour work shift,

the last 4 hours of their shift would have to average less than 25 ppm to keep the total

work shift TWA exposure under 25 ppm. By using both the peak and TWA CO-exposure data from a dosimeter, a manager can make informed decisions in the field,

thereby preventing hazardous smoke exposure, and yet accomplishing work 

objectives.

3
4

The great advantage of the datalogging dosimeter is data storage. Data storage, transfer to a computer, and graphing of each CO-exposure “profile” allows the crew

supervisor or safety officer to identify which work activities and fireline situations

caused hazardous CO exposure during a work shift. Figure 2 shows a graph of CO

exposure prepared from such data. This record of exposure was taken from a firefighter holding fireline and mopping up during a burnout operation in August 1994 

at the Libby Complex, Libby, Montana (Reinhardt and others 1994a).

In this particular case, local winds increased during the afternoon firing operation,

causing significant smoke exposure among personnel holding line. This can be seen

by many vertical peaks in CO concentrations between 1630 and 1900 hours. These

peaks correspond to periods of dense smoke from the fire. From such graphs, daily

CO exposure can be reviewed by managers and safety officers, and crews can be

trained to recognize unsafe conditions. In a comprehensive smoke-exposure management program, exposure data can be tracked over many years to evaluate whether

smoke-exposure management strategies are effective. Each data file from the 

datalogger becomes a permanent record of the CO exposure, which is an important

consideration when employer liability issues are of concern.

Figure 2—Carbon monoxide exposure at wildfire, August 1994. This record of exposure was taken from a

firefighter holding fireline and mopping up during a burnout operation at the Libby Complex, Libby, Montana

(Reinhardt and others 1994a).
The following equipment is needed for calibration and sampling with one of the

advanced datalogging electronic dosimeters:

• Electronic datalogging CO dosimeters.

• Replacement CO sensors, filters, and batteries.

• Leak-free tubing and a squeeze bottle of soapy water to check for leaks.

• Certified standard calibration gas mix of CO in air, the concentration of which 

should be roughly 50 percent of the highest expected exposure, or as specified 

by the manufacturer.

• Certified quality-control calibration check gas mix of CO in air, the concentration of

which should be roughly 50 percent of the calibration gas.

• Grade 5 nitrogen or air for baseline zero check.

• High-pressure regulator for each gas and the necessary adapter fittings to deliver

the gases to the dosimeters.

• Soap film flowmeter or calibrated rotameter for setting flow rates if using adjustable

regulators (optional).

To be in compliance with OSHA regulations, an effective monitoring program must

include adequate documentation of calibrations, sampling, and data analysis. Signed

and dated records are best for all aspects of the program. A permanent record of 

calibration and maintenance data should be maintained in a notebook. Figure 3a

shows the minimum calibration check data that should be recorded on each day of

monitoring. Identify serial numbers of equipment and keep copies of certifications 

from gas manufacturers—attention to all details is necessary to prove the validity 

of the results.

Working with a straightforward data form helps ensure that all necessary information 

is obtained. Figure 3b shows an example of a data form. Forms should be simple and

to the point, with prompts for basic daily information concerning the fire and the 

firefighter name and duties. Shift and datalogger start and stop times must be noted,

and additional information about events such as smoke intensity during the work shift,

cigarette breaks, and exposure to engine exhaust may prove useful for data 

interpretation.

Many choices of equipment, strategy, and protocol may be made when planning a

monitoring program. By adhering to a few basic steps, managers can easily obtain

accurate and representative CO exposure data. On the other hand, shortcuts can lead

to errors and useless data. A general calibration and monitoring protocol is outlined

below to help ensure that results are dependable. Whether establishing a monitoring

program for a prescribed burning program or a large wildfire, the calibration and equipment management for the monitoring program is best assigned to one or two

individuals. The actual monitoring may be accomplished by any responsible field person after some introductory training. Details of the operation of a particular model of

datalogger are described in the owners manuals and will not be repeated here.

5

Basic Equipment

Suggested Protocol
Date Firename: Location:

Datalogger results (ppm CO)

Date Time GasID AB C D E F

Pre Zero:

Pre QCCK:

Post Zero:

Post QCCK:

Calibrationcheckedby: Signature:

Date: Fire name: Location:

Site data

W indspeed: Humidity Fueltype/loading

Carbon Monoxide Exposure Monitoring Date

Datalogger Firefighter: Datalogger Firefighter:

A Time Activities/smoke B Time Activities/smoke

shiftstart: shiftstart:

logstart: logstart:

logstop: logstop:

shiftstop: shiftstop:

Notes: Notes:

Datalogger Firefighter: Datalogger Firefighter:

C Time Activities/smoke D Time Activities/smoke

shiftstart: shiftstart:

logstart: logstart:

logstop: logstop:

shiftstop: shiftstop:

Notes: Notes:

Datalogger Firefighter: Datalogger Firefighter:

E Time Activities/smoke F Time Activities/smoke

shiftstart: shiftstart:

logstart: logstart:

logstop: logstop:

shiftstop: shiftstop:

Notes: Notes:

Data recorder (signature): Location/date:

Figure 3—(A) data form for daily use in the field and (B) exposure monitoring data form.

6

A

B
The objective of calibration is to first set the zero baseline of the datalogger in CO-free

conditions, and then to set the upper end of the range to a known concentration of CO

in air. After calibration, the datalogger should read accurately between these values.

The accuracy of the calibration is confirmed each day by the quality-control check

(QCCK) results described below. For many dataloggers, calibration is conducted

monthly or when necessary as indicated by daily QCCK results.

Calibration can be accomplished in less than an hour by using both a cylinder of 

nitrogen (or pure air) and a certified (or primary standard) calibration mix containing

CO in air. These items and the necessary adapters for the electronic dataloggers are

available from the manufacturers as a standard kit. If ambient CO is less than 1 ppm,

the nitrogen (or pure air) cylinder is unnecessary. There are many sizes and configurations of cylinders for gases. The best choice depends on the number of dataloggers 

or dosimeters that must be calibrated, the U.S. Department of Transportation (DOT)

compliant transportation options available, and the gas regulators available. Some

popular cylinder sizes that emphasize low cost and high transportability are listed 

in table 1.

Table 1—Typical calibration gas cylinder options

DOT cylinder Approximate number of 

designation Capacity Size Weight calibrations per cylinder 

Liters Inches Pounds

39 17 3 x 11 1.1 25

39 105 3 x 14 2.3 200

3AL 1,019 7 x 16 15 1,700

The type 39 cylinders are nonrefillable but portable. The 3AL cylinders are still small

and light but are better for larger monitoring programs where continuity of calibration

gases is important because they contain more gas. Compressed gas cylinder transportation must be done according to DOT regulations. Many shippers (especially

airlines) will not handle pressurized cylinders of gas, even though the CO-air mixtures

and nitrogen are classified as relatively nonhazardous “Compressed Gas-NOS.”

Finally, be aware that the regulators for gas delivery have specific fittings for each type

of gas, and these are not interchangeable among many styles of disposable cylinders.

Before working with compressed gases, make sure that personnel know how to 

handle them safely and that the work space is properly ventilated.

7

Calibration
At the PNW lab in Seattle, the calibration gas concentration is 125 ppm, about 50 

percent of the highest CO concentration expected. By using the appropriate regulator

for each cylinder, a calibration adapter connected to the regulator by tubing delivers

the gas supply to the datalogger. The adapter must fit snugly over the sensor, surrounding it with only the selected gas. If an adjustable regulator is used, the gas flow

should be set to a constant rate recommended by the manufacturer--use an inline

rotameter to ensure that gas is flowing to the sensor during the entire calibration. All

connections must be leak free, so each connection is checked for leaks before calibrating. (Apply soapy water to the connections, then pressurize with gas and look for

bubbles.) The datalogger is consecutively exposed to the nitrogen (or clean air) and

the calibration gas (fig. 4). After equilibrating for a short period, the displayed CO 

values should be within 1 ppm of the expected value. If not, adjust the calibration reading according to the manufacturer’s recommendation. After reexposing the datalogger

to nitrogen and ensuring that a zero ppm reading is attained, the instrument is calibrated. If the values displayed by the datalogger are inaccurate or variable during the

calibration process, the setup should be doublechecked for leaks and proper gas flow,

and maintenance performed on the instrument if necessary.

Dosimeters are equipped with an audible alarm activated when CO levels reach a

specified concentration. On many models, the alarm can be adjusted to serve as an

early warning device to alert firefighters before the CO exposure becomes hazardous.

8

Alarm Adjustment

Figure 4—Calibration procedure.

Leak check

system

Run zero gas,

adjust within

1 ppm of zero

New dosimeter

or maintenance

just completed

Failed QC check

or 1 month since

last calibration

Check system

for leaks,

maintan

dosimeter

Not within

1 ppm of zero

Run calibration

gas, adjust within

1 ppm of zero

Rerun zero gas Reads within

1 ppm of zero

Ready for

daily QC check
Setting the alarm level to a CO concentration that is too low could cause workers to

develop a habit of ignoring the alarm or removing the dosimeter; the alarm level

should be selected with care. The alarm is set to the desired ppm value by a simple

adjustment.

At the beginning of each work shift or sample period, the datalogger is run through 

a brief QCCK evaluation. This assesses the performance of the instrument for the 

day, ensures that the instrument is correctly calibrated, and gives an indication of the

stability and remaining life of the sensor. All pertinent data should be recorded on the

zero and QCCK data form (fig. 3a). Ideally, the datalogger calibration is tested before

and after each work shift to ensure that the instrument was functioning properly during

the monitoring period. Like the calibration, the QCCK process uses the same tubing

and adapters but should require less time per datalogger. Skipping the QCCK process

leaves an important gap if the goals of the CO monitoring program include obtaining

data that can stand up to critical scrutiny.

The QCCK is a two-step process (fig. 5). First, the zero reading of the datalogger is

recorded in clean ambient air to ensure that the instrument will not give false high

results. If the ambient air is not free of CO, as during atmospheric inversions or near

engine exhaust, purified air or nitrogen is used. Unlike calibration, it is important to

9

Quality-Control Check

Passed last calibration

Leak-check system

Run zero gas

Not within

3 ppm of target

Rerun zero gas

Reads within

3 ppm of zero

Ready for use

Not within

3 ppm of zero

Recalibration

necessary

Not within

3 ppm of zero

Reads within

3 ppm of target

Run

QCCK gas

Reads within

3 ppm of zero

Figure 5—Daily quality-control check.
leave the zero levels unadjusted. After recording the zero reading, the response of 

the instrument is tested against the independently prepared QCCK gas. Like the 

calibration gas, this QCCK gas should be a mix of CO in air, but in a range more 

representative of average exposure levels. At the PNW lab, this gas is procured at

roughly 50 ppm.

The independently prepared QCCK gas identifies whether leaks or recording errors

have occurred during calibration and verifies the accuracy of the response of the

instrument in a range more consistent with actual exposure of firefighters. The QCCK

gas also checks on the linearity of the response of the datalogger between zero and

the upper calibration point. Datalogger responses that deviate more than a few ppm

from either the zero or QCCK value should be considered failure of the QCCK

process. In that case, the datalogger may need to be recalibrated or repaired before

being used.

The process of selecting firefighters for monitoring has an effect on the data collected,

and can cause overestimation or underestimation of exposure if not done in accordance with the objectives of the monitoring program. Random selection is the best

approach when objectives of monitoring include tracking the long-term effectiveness of

smoke-exposure management efforts. Random selection of a representative firefighter

from among the entire crew (or group of drivers, pilots, or fire-camp personnel) is used

to help assure that the results are statistically representative of all crew members.

Choosing from volunteers does not guarantee representative results. For example, a

particular volunteer may avoid smoke because they are concerned about their health;

their CO exposure would underestimate the exposure of those who do not avoid

smoke. Include all workers in the selection pool to avoid unrepresentative results.

An alternative strategy is to select a likely most-exposed individual. Although this can

overestimate the crews' exposure to smoke, it also provides for a margin of safety in

hazardous situations. This is a good strategy when the objective is to prevent any CO

overexposure, but sometimes selecting the most-exposed individual in advance is

impractical.

Once the firefighter is chosen, the datalogger is switched into the logging mode and

the start time recorded (fig. 3b). The datalogger is attached to the firefighter’s clothing

with the sensor in an unobstructed position in the breathing zone, within about 18

inches of the subject’s face, and CO-exposure monitoring begins (fig. 6).

Actual CO exposure is continuously recorded by the datalogger. The display for some

models will cycle through a readout of current CO concentration, shift TWA, and peak

exposure. If the CO alarm sounds during the shift, the crew supervisor can use this

information to decide whether to move the crew to safety. We recommend that the

TWA exposure to CO should be maintained below 25 ppm, with no peak exposure

over 200 ppm. Using the field data form (fig. 3b), record firefighter activity, apparent

smoke concentration, and the time of day when conditions change to help interpret the

data. During use, avoid exposing the datalogger sensor to cigarette smoke or engine

exhaust if these are not representative of crew exposures. An exception may be made

for sawyers and swampers, who may endure more CO exposure than others because

of chainsaw operation. Crew managers can measure this exposure by using the datalogger and take action if CO exposure during these tasks exceeds recommended

limits. Nothing else needs to be done with the datalogger until the end of the shift.

10

Monitoring
At the end of the shift, the instrument is removed and the time is recorded (fig. 3b).

After this, the zero and QCCKs are repeated to ensure that the datalogger gave valid

results during the entire shift (fig. 4). All data are recorded on the appropriate forms

(fig. 3a). Then the stored datalogger results can be downloaded to a personal computer through an adapter to an RS-232 port. If the user is working in the field away

from power, a portable computer and a small battery for the RS-232 adapter can be

used to transfer the data.

To comply with OSHA and state regulations, notify workers of all monitoring results

within 30 days, maintain adequate records, and train workers about the health hazards

associated with their work. To ensure the adequacy of the records, the calibration

gases should be certified standards, and detailed, signed records of calibrations,

QCCKs, and all monitoring results should be kept on file. For assistance with technical

questions, planning the program, or interpreting results, consult an industrial hygienist.

11

Figure 6—Datalogger in the breathing zone.
Carbon monoxide-exposure data can be used to estimate exposure to other components of smoke, including benzene and respiratory irritants such as acrolein,

formaldehyde, and respirable particulate matter. As in the case of CO, each of these

pollutants has its own occupational exposure limit. When assessing exposure to multiple irritants in smoke, their combined impacts should be considered because they all

affect the respiratory system (benzene is excluded because it is not a respiratory 

irritant). One way to do this is with a combined exposure index (fig. 7).

By using CO as a surrogate measurement, exposure estimates are first obtained for

the respiratory irritants. Table 2 contains several equations relating pollutant exposure

to CO in smoke. These equations were developed at PNW from data obtained at wildfires in the Western United States and may not work for other regions.2 The benzene

equation does not apply if sources of gasoline vapor or engine exhaust affect the

worker, because the equation was developed only for wood smoke, not the additional

benzene from those sources. Exposure to each irritant in smoke is estimated by applying the appropriate regression equation for each irritant. Next, the combined exposure

is calculated by summing each irritant exposure divided by its exposure limit, to calculate a unitless index of exposure, Em. This index must be maintained below 1.0 to

ensure a hazard-free workplace, as it was in figure 7.

12

Carbon Monoxide

and Other Smoke

Hazards

Figure 7—Irritant exposure calculated from a firefighter on the 1994 Libby Complex wildfire, Libby, Montana.

2 Reinhardt, T.E.; Ottmar, R.D. [In prep.]. Smoke exposure at 

western wildfires.
For example, assume that the TWA CO exposure of a firefighter is 23 ppm. By using

the four regression equations, the following tabulation shows the corresponding 

pollutant exposures:

TWA exposure Recommended TWA

Pollutant regression result exposure limit

Formaldehyde (HCHO) 0.08 ppm 0.3 ppm

Respirable particulate 2.15 mg/m3 3 mg/m3

(PM3.5)

Acrolein (ACRO) .01 ppm .1 ppm

Benzene (BENZ) .03 ppm .3 ppm

13

Table 2—Equations to correlate respiratory irritants to CO in smoke

Pollutant Units Regression equation for analyte r2 value

Formaldehyde ppm [HCHO] = 0.0034x[CO]+0.003 .77

Respirable

Particulate mg/m3 [PMc.5] = 0.049x[CO]=.88 .74

Acrolein ppm [ACRO]=0.0004x[CO]=0.004 .57

Benzene ppm [BENZ]=0.0011x[CO]+0.003 .95
The combined irritant exposure is calculated as shown in the following equation:

[HCHO] [PM3.5] [ACRO] EM = —————+————— +————— 0.3 3 0.1

EM = [0.08] [2.15] [0.01] = 1.08 . —————+————— +————— 0.3 3 0.1

Because the irritant exposure exceeds 1.0, it must be reduced to achieve compliance

with recommended irritant exposure limits. Although the firefighter was not overexposed to CO, the exposure to respiratory irritants should be reduced. With proper

advance training in respirator use, a lightweight half-mask respirator for fine particles

could achieve this irritant control, but CO exposure must continue to be monitored

closely in similar situations. This is especially important when using a respirator,

because although it affords relief from respiratory tract irritation, it does nothing to

reduce CO exposure.

These straightforward calculations provide much more information from the datalogger—not only the CO data, but also a good indication of what the exposure is to

respiratory irritants and benzene. Using this approach alleviates the need to monitor

each pollutant separately. The correlations give a more complete picture of smoke

exposure, providing managers with the information necessary to judge whether 

respiratory protection is needed to control irritant exposure, or whether the CO 

hazard still is high enough to warrant moving the crew into clean air.

Smoke-monitoring programs can be easy to implement when using CO dataloggers.

Data collection can be done at both prescribed burns and wildfires with a minimal

investment of time. For that investment, managers can gain valuable information to

help recognize and control unhealthy smoke-exposure situations. The simplest

dosimeter can alert firefighters to high levels of CO and other smoke-related hazards.

Objective smoke-exposure information removes the guesswork when making decisions about firefighting strategy and crew safety, and provides detailed data when

reviewing events for planning, training, and management purposes. By using this guide

to start a comprehensive smoke-exposure monitoring program, you can be assured

that the right steps will be taken to collect useful information. Once the data collection

becomes routine, managers can evaluate the results and determine whether smokeexposure management strategies are working. When managers can reduce the health

stress that smoke exposure causes, fire crews will have more work capacity and less

illness and lost work days, thereby resulting in a more productive workforce.

14

Conclusion
Reinhardt, T.E.; Black, J.; Ottmar, R.D. 1994a. Smoke exposure at Pacific Northwest

wildfires. [Place of publication unknown]: [Publisher unknown]; final report; Radian

Corporation contract 53-05m6-2-0032. 129 p. Available from: U.S. Department of

Agriculture, Forest Service, Pacific Northwest Research Station, 4043 Roosevelt Way

NE, Seattle, WA.

Reinhardt, T.E.; Hanneman, A.H.; Ottmar, R.D. 1994b. Smoke exposure at prescribed burns: health hazards of smoke. Missoula, MT: U.S. Department of Agriculture,

Forest Service, Missoula Technology and Development Center: 2-3.

Manufacturers for purchasing CO dataloggers

Industrial Scientific Corporation

1001 Oakdale Road

Oakdale, PA 15071-1500

(412) 788-4353

(800) DETECTS

Mine Safety Appliances

P.O. Box 426

Pittsburgh, PA 15230

(800) MSA-2222

National Draeger, Incorporated

101 Technology Drive

Pittsburgh, PA 15275

(412) 787-8383

(800) 922-5518

15

Literature Cited

Appendix
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Reinhardt, Tim E.; Ottmar, Roger D.; Hallett, Michael J. 1999. Guide to monitoring smoke exposure of wildland firefighters. Gen. Tech. Rep. PNW-GTR448 . Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station. 15 p.

Fire managers and safety officers concerned with smoke exposure among fire

crews can use electronic carbon monoxide (CO) monitors to track and prevent

overexposure to smoke. Commonly referred to as dosimeters, these lightweight

instruments measure the concentration of CO in the air the firefighter’s breathe.

This guide outlines the protocol developed for sampling smoke exposure among

firefighters with CO dosimeters. It provides a basic template for managers and

safety officers interested in establishing their own smoke-exposure monitoring

program.

Keywords: Fire, smoke, human health, occupational exposure, safety, smoke

exposure.

The Forest Service of the U.S. Department of

Agriculture is dedicated to the principle of multiple

use management of the Nation’s forest resources

for sustained yields of wood, water, forage, wildlife,

and recreation. Through forestry research, cooperation with the States and private forest owners, and

management of the National Forests and National

Grasslands, it strives—as directed by Congress—to

provide increasingly greater service to a growing

Nation.

The U.S. Department of Agriculture (USDA) prohibits

discrimination in all its programs and activities on the

basis of race, color, national origin, gender, religion,

age, disability, political beliefs, sexual orientation, or

marital or family status. (Not all prohibited bases

apply to all programs.) Persons with disabilities who

require alternative means for communication of

program information (Braille, large print, audiotape,

etc.) should contact USDA’s TARGET Center at

(202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA,

Director, Office of Civil Rights, Room 326-W, Whitten

Building, 14th and Independence Avenue, SW,

Washington, DC 20250-9410 or call (202) 720-5964

(voice and TDD). USDA is an equal opportunity

provider and employer.

Pacific Northwest Research Station

333 S.W. First Avenue

P.O. Box 3890

Portland, Oregon 97208-3890
U.S. Department of Agriculture

Pacific Northwest Research Station

333 S.W. First Avenue

P.O. Box 3890

Portland, OR 97208

Official Business

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