Fire and Environmental Research Applications Team

Effects of Smoke Exposure on Firefighter Health

A Screening-Level Assessment of the Health Risks of Chronic Smoke Exposure for Wildland Firefighters

Abstract -- A screening health risk assessment was performed to assess the upper-bound risks of cancer and noncancer adverse health effects among wildland firefighters performing wildfire suppression and prescribed burn management. Of the hundreds of chemicals in wildland fire smoke, we identified 15 substances of potential concern from the standpoints of concentration and toxicology; these included aldehydes, polycyclic aromatic hydrocarbons, carbon monoxide, benzene, and respirable particulate matter. Data defining daily exposures to smoke at prescribed burns and wildfires, potential days of exposure in a year, and career lengths were used to estimate average and reasonable maxim um career inhalation exposures to these substances. Of the 15 substances in smoke that were evaluated, only benzene and formaldehyde posed a cancer risk greater than 1 per million, while only acrolein and respirable particulate matter exposures resulted in hazard indices greater than 1.0. The estimated upper-bound cancer risks ranged from 1.4 to 220 excess cancers per million, and noncancer hazard indices ranged from 9 to 360, depending on the exposure group. These values only indicate the likelihood of adverse health effects, not whether they will or will not occur. The risk assessment process narrows the field of substances that deserve further assessment, and the hazards identified by risk assessment generally agree with those identified as a concern in occupational exposure assessments.

Booze, Thomas F.; Reinhardt, Timothy E; Quiring, Sharon J.; Ottmar, Roger D. 2004. A screening-level assessment of the health risks of chronic smoke exposure for wildland firefighters. Journal of Occupational and Environmental Hygiene. 1:296-306
Full text [.pdf 109 kb]

Baseline Measurements of Smoke Exposure Among Wildland Firefighters

Abstract -- Extensive measurements of smoke exposure among wild-land firefighters are summarized, showing that firefighters can be exposed to significant levels of carbon monoxide and respiratory irritants, including formaldehyde, acrolein, and respirable particulate matter. Benzene was also measured and found to be well below permissible exposure limits, with the highest concentrations occurring among firefighters working with engines and torches burning petroleum-based fuel. Exposures to all pollutants were higher among firefighters at prescribed burns than at wildfires, while shift-average smoke exposures were lowest among firefighters who performed initial attack of wildfires in the early stages of the fires. Smoke exposure reaches its highest levels among firefighters maintaining fire within designated firelines and performing direct attack of spot fires that cross firelines. These events and the associated smoke exposures were positively correlated with increasing ambient wind speeds, which hamper fire management and carry the convective plume of the fire into firefighters' breathing zone. The pollutants measured in smoke were reasonably well-correlated with each other, enabling estimation of exposure to multiple pollutants in smoke from measurements of a single pollutant such as carbon monoxide.

Reinhardt Timothy E.; Ottmar, Roger D. 2004. Baseline measurements of smoke exposure among wildland firefighters. Journal of Occupational and Environmental Hygiene. 1: 593-606.
Full text [.pdf 711 kb]

Ottmar, Roger D; Reinhardt, Timothy R. 2001. Smoke exposure among fireline personnel. Chapter 3.4, 51-57. In: Hardy, Colin C.; Ottmar, Roger D.; Peterson, Janice L; Core, John E.; Seamon, Paula, eds. and comps. Smoke management guide for prescribed and wildland fire: 2001 edition. PMS 420-2. NFES 1279. Boise, ID: National Wildfire Coordination Group. 226 p.
Full Text [.pdf]. [Instructions for ordering]

Smoke Exposure at Western Wildfires

Abstract -- Smoke exposure measurements among firefighters at wildfires in the Western United States between 1992 and 1995 showed that altogether most exposures were not significant, between 3 and 5 percent of the shift-average exposures exceeded occupational exposure limits for carbon monoxide and respiratory irritants. Exposure to benzene and total suspended particulate was not significant, although the data for the latter were limited in scope. The highest short-term exposures to smoke occurred during initial attack of small wildfires, but the shift-average exposures were less during initial attack than those at extended (project) fire assignments because of unexposed time during the shift. Among workers involved in direct attack of actively burning areas and maintaining fireline boundaries, peak exposure situations could be several times greater than recommended occupational exposure limits for short-term exposures. The study found that exposure to acrolein, benzene, formaldehyde, and respirable particulate matter could be predicted from measurements of carbon monoxide. Electrochemical dosimeters for carbon monoxide were the best tool for routinely assessing smoke exposure, so long as quality assurance provisions were included in the monitoring program. Suggested procedures for reducing overexposure to smoke include (1) hazard awareness training, (2) routinely monitoring smoke exposure, (3) evaluating health risks and applicable exposure criteria, (4) improving health surveillance and injury recordkeeping, (5) limiting use of respiratory protection when other mitigation is not feasible, and (6) involving workers, managers, and regulators to develop a smoke exposure management strategy.

Reinhardt, Timothy E.; Ottmar, Roger D. 2000. Smoke exposure at western wildfires. Res. Pap. PNW-RP-525. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 72 p.
Abstract and full text [.html]

Smoke Exposure Among Firefighters at Prescribed Burns in the Pacific Northwest

Abstract -- Smoke exposure measurements among firefighters during prescribed burns in the Pacific Northwest between 1991 and 1994 showed that a small but significant percentage of workers experienced exposure to carbon monoxide and respiratory irritants that exceeded occupational exposure limits. This most often was caused by unfavorable winds or fire behavior and occurred mostly among workers involved in maintaining the fire within the prescribed boundaries. Smoke exposure in such peak exposure situations was up to three times above recommended limits. Exposure to acrolein benzene, formaldehyde, and respirable particulate matter could be predicted from measurements of carbon monoxide. Electronic dosimeters were the best tool to assess smoke exposure routinely, so long as quality assurance concepts were included in the monitoring program.

Reinhardt, Timothy E.; Ottmar, Roger D.; Hanneman, Andrew J.S. 2000. Smoke exposure among firefighters at prescribed burns in the Pacific Northwest. Res. Pap. PNW-RP-526. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 45 p.
Abstract and full text [.html

Guide to Monitoring Smoke Exposure of Wildland Firefighters

Abstract -- 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.

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.
Abstract and full text [.html]

Smoke Exposure Among Wildland Firefighters: A Review and Discussion of Current Literature

Abstract -- This paper reviews and summarizes literature about smoke exposure and the resulting adverse health effects among wildland firefighters Many studies have been done on this problem between 1973 and 1995 Overall the data indicate that smoke exposure at wildfires and prescribed fires is usually no more than an inconvenience, but on occasion it approaches or exceeds legal and recommended occupational exposure limits Management action is necessary to bring all smoke exposures into compliance with occupational safety regulations.

Reinhardt, T.E.; Ottmar, R.D. 1997. Smoke exposure among wildland firefighters: a review and discussion of current literature. Gen. Tech. Rep. PNW-GTR-373. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.68 p.
Abstract and full text [.html] 

Fire and Environmental Research Applications Group. 1995. Smoke exposure at prescribed burns. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station [not paged]. Brochure.

Reinhardt, T.; Hanneman, A.; Ottmar, R. 1994. Smoke exposure at prescribed burns. Final report; Radian Corporation. Available from: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 4043 Roosevelt Way, Seattle, WA.

Monitoring Firefighter Exposure to Air Toxins at Prescribed Burns of Forest and Range Biomass

Abstract -- A variety of potent air toxins are in the smoke produced by burning forest and range biomass. Preliminary data on flrefighter exposures to carbon monoxide and formaldehyde at four prescribed burns of Western United States natural fuels are presented. Formaldehyde may be correlated to carbon monoxide emissions. The firefighters' exposures to these compounds relative to workplace standards are discussed.

Reinhardt, Timothy E. 1991. Monitoring firefighter exposure to air toxins at prescribed burns of forest and range biomass. Res. Pap. PNW-RP-441. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 8 p.
Abstract and full text [.html]

Other Sources of Information

• The National Library of Medicine and National Institutes of Health Database. Search for "firefighter smoke exposure" at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed
• U.S. Environmental Protection Agency. General information about smoke and health. http://www.airnow.gov/index.cfm?action=topics.smoke_events
• How Smoke from Fires Can Affect Your Health. A brochure published by the EPA. http://www.epa.gov/airnow//smoke/Smoke2003final.pdf

Team Lead: Roger Ottmar

Collaborators:

This research is funded by