Pulmonary function and respiratory symptoms in forest firefighters.

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. FEV1, and FEF25 75. The preshift to midshift decreases were 0.089 L, 0.190 L, and 0.439 I/sec. respectively, with preshift to postshift declines of 0.065 L, 0.150 L, and 0.496 L/sec. Mean individual declines for FVC, FEV1 and FEF25 75 of 0.033 L, 0.104 L, and 0.275 I/sec. respectively, also were noted in the cross-season analysis. The FEV1 changed significantly (p < 0.05). The use of wood for indoor heat also was associated with the declines in FEV1. Although annual lung function changes for a small subset (n = 10) indicated reversibility of effect, this study suggests a concern for potential adverse respiratory effects in forest firefighters.