Health Hazard Evaluation Report: HETA 99-0173-2856, Turnbull National Wildlife Refuge, Cheney, Washington.

摘要

In April 1999, the U.S. Park Service, Turnbull National Wildlife Refuge (TNWR), Cheney, Washington, asked NIOSH to evaluate exposure to chainsaw exhaust among forestry workers. Although workers had not reported any symptoms related to chainsaw exhaust, management wanted to have some documentation of their exposure. Six to eight foresters are employed to thin the forest of pine trees up to 22 inches in diameter. Exposure to airborne carbon monoxide (CO), benzene, aldehydes, and polynuclear aromatic hydrocarbons (PNAs) was evaluated during four days of sampling with wind conditions ranging from calm to 11 miles per hour (mph). Also, carboxyhemoglobin (COHb) levels in each forester were estimated by measuring CO in exhaled breath. On two days of cutting larger trees during light wind conditions (up to 7 mph), full-shift exposure to CO ranged from 8 to 31 parts per million (ppm), with 40% of the exposures exceeding the most protective evaluation criterion of 25 ppm. Peak CO exposures (up to 1100 ppm) were found to occur primarily when foresters were bent or kneeling to cut the stumps of larger trees close to ground level. Estimated COHb levels ranged up to 4.9% with 33% of COHb levels exceeding the evaluation criterion of 3.5%. On two days of cutting smaller trees during wind conditions up to 11 mph, no full-shift CO exposures exceeded the evaluation criterion.