LUNG HEALTH IN RELATION TO HYDROGEN-SULFIDE EXPOSURE IN OIL AND GAS WORKERS IN ALBERTA, CANADA

A study was undertaken to assess pulmonary health effects of hydrogen sulfide (H2S) exposure in a group of workers (n = 175) extracting and processing oil and natural gas in west-central Alberta. Exposure to H2 S was assessed by questioning the workers about ''exposures strong eno ugh to cause symptoms,'' and exposures that resulted in loss of consci ousness (a ''knockdown''). Exposures strong enough to cause symptoms w ere reported by 34% of the workers. Fourteen workers (8%) reported hav ing had a knockdown. Exposures severe enough to cause symptoms were no t associated with lower spirometric values or excess symptoms. Knockdo wns were not associated with lower spirometric values but were associa ted with statistically significant excesses of (1) shortness of breath while hurrying on the level or walking up a slight hill (OR = 3.55; 9 5%Cl = 1.02-12.4); (2) wheeze with chest tightness (OR = 5.15; 95%Cl = 1.29-20.6); and (3) attacks of wheeze (OR = 5.08; 95%Cl = 1.28-20.2). The pattern of excess respiratory symptoms is consistent with bronchi al hyperresponsiveness, which has been documented in studies of high-l evel exposure to other irritant gases. Additional study is warranted a nd should include assessment of bronchial reactivity. (C) 1997 Wiley-L iss, Inc.