An updated mortality study of workers in three major United States refineries and chemical plants

Abstract

A historical cohort study of refinery and chemical plant workers, originally observed from 1970 to 1977, was updated to the end of 1982. This cohort included 25,321 active, retired, and terminated workers at the Exxon refineries and chemical plants in Baton Rouge, Louisiana; Baytown, Texas; and Bayway/Bayonne, New Jersey. An emphasis was placed on the cancers previously reported to be increased in at least one petrochemical worker population. The population included a high proportion of retirees, providing adequate work experience and latency to evaluate risks associated with employment. Vital status was determined for 98.3% of the population and death certificates were obtained for 99.9% of the decedents. Mortality for "all causes of death" (standardised mortality ratio (SMR) = 89, 95% confidence interval (95% CI) 87-91) and for "all cancers" (SMR = 94, 95% CI 89-100) were lower than expected based on state rates. History of cigarette smoking collected from individual medical records and summarised work histories were used for subgroup analyses. There was no indication that cancers of primary interest were increased; however, blue collar workers at one plant had raised rates of kidney cancer (SMR = 246, 95% CI 146-390), which may require further evaluation.