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Health hazard evaluation report: HETA-2008-0245-3127, determining base camp personnel exposures to carbon monoxide during wildland fire suppression activities - California.

McCleery RE; Almazan A; Dowell CH; Snawder J
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, HETA 2008-0245-3127, 2011 May; :1-32
In July 2008, NIOSH received a request for an HHE at a base camp supporting the Siskiyou and Ukonom fires in the Klamath National Forest, California. Federal agency managers submitted the request due to concerns about CO exposure among personnel who work in the base camp supporting wildland firefighters during fire suppression activities. Headaches were listed as the primary health concern. On August 13-14, 2008, NIOSH investigators conducted PBZ air monitoring for CO exposure and measured blood COHb levels for 19 nonsmoking forestry personnel and contractors and performed GA air sampling for CO in the base camp. Employees' average work shift CO exposures were low (< 6 ppm). However, peak CO concentrations exceeded OELs; 7 of 19 (37%) exceeded the ACGIH excursion limit of 125 ppm, 5 of 19 (26%) exceeded the NIOSH ceiling limit of 200 ppm, and 4 of 19 (21%) exceeded the 1000 ppm upper limit of the instrument (approaching the 1200 ppm NIOSH IDLH level for < 1 minute). The GA monitors located throughout the base camp indicated average CO concentrations of less than 2 ppm with a peak reading of 20 ppm. Over the 2-day period, 19 nonsmoking employees had COHb measurements taken. Although not directly comparable to the ACGIH BEI (end of shift, 8-hour COHb measurement of 3.5%), 3 of the 19 (16%) nonsmoking employees met or exceeded a COHb measurement of 3.5%, an indicator of a 25 ppm, 8-hour TWA CO exposure. Only one of these employees had a corresponding peak PBZ air CO concentration exceeding the ACGIH excursion limit and none had a corresponding peak PBZ air CO concentration that exceeded the NIOSH ceiling limit. The levels of COHb we found among employees at the base camp have not been documented to cause symptoms that can result from short-term, higher levels of CO exposure. However, the combination of consecutive 16-hour work shifts, continuous exposure to forest fire smoke, and hot environmental conditions could explain headaches reported in the HHE request. NIOSH investigators recommend developing a base camp air monitoring program for particulates and CO and limiting the number of personnel working extended shifts as well as the frequency and duration of extended work shifts. We also recommend developing CO and particulate action levels for use during future fire events, taking into consideration employee extended work shifts. A program should also be established to increase base camp personnel's awareness of heat stress.
Fire-fighting; Fire-fighters; Emergency-response; Emergency-responders; Fire-hazards; Fire-safety; Air-quality-monitoring; Air-sampling; Breathing-zone; Forestry; Forestry-workers; Blood-gas-analysis; Exposure-assessment; Exposure-levels; Exposure-limits; Permissible-limits; Lethal-concentrations; Time-weighted-average-exposure; Hazard-Confirmed; Region-9; Smoke-inhalation; Hot-environments; Work-intervals; Particulates; Heat-stress; Heat-exposure; Author Keywords: carbon monoxide; CO; carboxyhemoglobin; COHb; base camp; firefighter; wildland forest fire
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Field Studies; Hazard Evaluation and Technical Assistance
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NIOSH Division
Priority Area
Construction; Transportation, Warehousing and Utilities
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National Institute for Occupational Safety and Health
Page last reviewed: October 26, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division