Cancer mortality among workers at a butadiene production facility.

A cohort study was carried out of mortality among 2749 male workers who had been employed for at least six months between 1943 and 1990 at a 1,3-butadiene production facility. Most of the members of the cohort were covered in two earlier studies, both of which found a statistically significant deficit for all causes of death and lower than expected mortality from most of the main causes of death. Both also found a statistically significant excess risk for lymphosarcoma, which was concentrated in workers who had been employed for fewer than 10 years, had first been employed before 1946 and had been employed in jobs with routine potential exposure. The purpose of the study reported here was to examine the patterns of mortality after addition of five years of follow-up, new eligible cohort members and complete information on work histories. We were able to obtain information on the vital status of all but 1.4% of the cohort: 1051 deaths had occurred between 1943 and 1990. Death certificates were obtained for all but 15 of the deceased men (1.4%). The standardized mortality ratio (SMR) for all causes of death is 88, and this low figure is statistically significant; the SMR for all cancers, 87, is not statistically significant. The SMR for all lymphohaematopoietic cancers is 143 (95% confidence interval, 100-200). The SMR for leukaemia is 112 (11 deaths), that for lymphosarcoma, 209 (nine deaths), that for other lymphomas, 126 (10 deaths) and that for Hodgkin's disease, 175 (four deaths). None of the latter SMRs is statistically significant.