Endotoxin exposure-response in a fiberglass manufacturing facility

Peak expiratory flow (PEF) and workplace exposure to endotoxin, phenolic resin, and formaldehyde were measured to investigate asthma symptoms and medication use among employees in a fiberglass wool manufacturing plant. Self-recorded PEF was obtained from 37 workers, for a total of 181 days off work and 187 days at work with concurrent personal exposure monitoring. Pre- and post-shift spirometry were obtained on at least 2 days. The 8 hr time-weighted average personal exposure ranges were endotoxin, 0.4–759 ng/m3; phenolic resin, 5.7–327 μg/m3; and formaldehyde, 1.2–265 μg/m3. Amplitude percent mean peak flow was associated with years since starting regular work in the highest endotoxin exposure area, although current assignment in that area was associated with reduced amplitude—evidence for a healthy worker effect. Exposure-response was analyzed by regression of lung function change on exposure using generalized estimating equations with robust variance estimates. Endotoxin exposure above 4 ng/m3 (8 hr time-weighted average) was associated with a decline in lung function across the work shift, and with drops in lung function 16–20 hr after exposure. Phenolic resin exposure was not consistently associated with decrements, and formaldehyde was not associated with decrements in lung function. © 1996 Wiley-Liss, Inc.