Mortality from brain tumor and other causes in a cohort of petrochemical workers

To evaluate a suspected excess of deaths due to brain tumor (BT) among petrochemical workers, a retrospective cohort mortality study was conducted among 7,595 men ever employed at a plant in Texas City, Texas, between 1941 and 1977. Among hourly employees, overall mortality was lower than expected from U.S. national rates [standardized mortality ratio (SMR) = 79]. However, 19 BT deaths (International Classification of Diseases, seventh revision, codes 193, 223, and 237) among hourly employees were observed as against 9.6 expected (SMR = 198), and with extension of the analysis to include BT deaths occurring in 1978 and 1979, 22 deaths were observed versus 10.7 expected (SMR = 206). Fifteen years or more after being hired, 19 of these workers died from BT versus 7.2 expected (SMR = 263), and the standardized mortality ratios increased with duration of employment to 377 for hourly workers who had worked over 20 years. Although nonoccupational etiologies cannot be dismissed, these data suggest an occupational etiology for certain BT deaths in petrochemical workers.