MORTALITY STUDY OF WORKERS IN 1,3-BUTADIENE PRODUCTION UNITS IDENTIFIED FROM A CHEMICAL WORKERS COHORT

摘要

The international Agency for Research on Cancer has given the designations of sufficient evidence of carcinogenicity of 1,3-butadiene in experimental animals and limited evidence of carcinogenic effect in humans. To investigate the carcinogenic effect in humans, we conducted a cohort mortality study amount 364 men who were assigned to any of three 1,3-butadiene production units located within several chemical plants in the Kanawha Valley of West Virginia, including 277 men employed in a U.S. Rubber Reserve Plant which operated during World War II. The butadiene production units included in this study were selected from an index developed by the Union Carbide Corporation, which listed for each chemical production unit within their South Charleston, West Virginia and Institute, West Virginia, plants all products, by-products, and reactants. Departments included in the study were those where butadiene was a primary product and neither benzene nor ethylene oxide was present. A total of 185 deaths were observed; the standardized mortality ratio (SMR) for all causes of death was 91, reflecting lower mortality among the study population than the U.S. population. The study found a significantly elevated standarized mortality ratio (SMR) for lymphosarcoma and reticulosarcoma based on four observed cases (SMR - 577; 95% CI = 157 - 1480), which persisted in an analysis using county referent rates. An excess of lymphosarcoma and reticulosarcoma among all workers and among workers with routine exposure to 1,3-butadiene was also observed in the only other cohort of 1,3-butadiene production workers previously studied. A statistically nonsignificant excess of stomach cancer was observed in the overall cohort (n = 5; SMR = 243; 95% CI = 79 - 568) that was most pronounced among workers or most pronounced among workers employed in the rubber reserve plant for 2 or more years (n = 5; SMR = 657; CI = 213 - 1530). We conclude that the results of this study add to the weight of evidence suggesting that butadiene is carcinogenic in humans. [References: 30]