Pulmonary Function and Respiratory Symptoms in Forest Firefighters Christine Betchley, MS, 1 Jane Q. Koenig, PhD , 1 * Gerald van Belle, PhD , 1 Harvey Checkoway, PhD , 1 and Timothy Reinhardt, MS 2 This study evaluated effects on respiratory health of forest firefighters exposed to high concentrations of smoke during their work shift. This is the first study of cross-shift respiratory effects in forest firefighters conducted on the job. Spirometric measurements and self- administered questionnaire data were collected before and after the 1992 firefighting season. Seventy-six (76) subjects were studied for cross-shift and 53 for cross-season analysis. On average, the cross-season data were collected 77.7 days after the last occupational smoke exposure. The cross-shift analysis identified significant mean individual declines in FVC, FEV 1 , and FEF 25–75 . The preshift to midshift decreases were 0.089 L, 0.190 L, and 0.439 L/sec, respectively, with preshift to postshift declines of 0.065 L, 0.150 L, and 0.496L/sec. Mean individual declines for FVC, FEV 1 and FEF 25–75 of 0.033 L, 0.104 L, and 0.275 L/sec, respectively, also were noted in the cross-season analysis. The FEV 1 changed significantly (p , 0.05). The use of wood for indoor heat also was associated with the declines in FEV 1 . Although annual lung function changes for a small subset (n 5 10) indicated reversibility of effect, this study suggests a concern for potential adverse respiratory effects in forest firefighters. Am. J. Ind. Med. 31:503–509, 1997. r 1997 Wiley-Liss, Inc. KEY WORDS: pulmonary function; forest firefighters; smoke exposure; respiratory health INTRODUCTION An estimated 80,000 firefighters per year in the United States are included in the control and management of wild fires and prescribed burns. Prescribed burns are defined as fires set by state or federal agencies for specific purposes such as to reduce fire hazards, re-vegetation, or disease control. On average, there are 70,000 prescribed fires covering more than two million acres during an active fire season [Ward et al., 1989]. The increasing need for land has resulted in people moving into critical areas between urban and wildland environments. Outdoor recreation is also increasing the use of wildlands. These changes require more fire protection and fire management, resulting in greater demands being placed on wildland and rural firefighters to provide protection [Ward et al., 1989]. Many of the components of the smoke from fire- suppression activities can cause immediate- and long-term adverse health effects. A previous study of air pollutant concentrations during prescribed burns [Reinhardt, 1989] found some wildland firefighters receiving short-term expo- sure levels of carbon monoxide .50 ppm (OSHA TWA exposure limit), which may increase the risk of cardiovascu- lar disease [Sammons and Coleman, 1974; Sharkey, 1991]. At lower levels, carbon monoxide produces headaches, nausea, irritation, impaired judgment, slower reaction times, and possibly accelerates atherosclerosis [Ward et al., 1989]. Aldehydes are present in smoke and are known to be irritants, and some (e.g., formaldehyde) are potential carcino- gens [Partanen, 1993]. Exposure to formaldehyde can pro- duce a loss of olfactory sensation, lacrimation and/or sore throats. Several hours of exposure at sufficient levels reduce 1 Department of Environmental Health and Epidemiology, 357234, University of Washington, Seattle, WA. 2 Radian Corporation, Seattle, WA. Contract Grant sponsor: Forest Service, USDA; Contract Grant number: PNW 91-0031. *Correspondence to: Jane Q. Koenig, Ph.D., Department of Environmental Health, 357234, University of Washington, Seattle, WA 98195-7234. Accepted for publication 22 October 1996 AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 31:503–509 (1997) r 1997 Wiley-Liss, Inc.