Environmental and epidemiologic studies were conducted at two styrene-butadiene-rubber (60476462) manufacturing facilities. Increased risk of malignancies of hematopoietic and lymphatic tissue, with particular consideration of leukemia, was examined. Styrene (100425), butadiene (106990), and benzene exposures were measured at both facilities. Vital status of all white male workers with more than 6 months employment (other than management) from the first operation of the facility until the date of the study was investigated. Expected numbers of cause specific deaths were compared to the observed deaths in the study population. Statistically significant differences were sought, and the standardized mortality ratio was determined. The mortality of workers with 6 months employment was analyzed separately. Correlations of length of employment with cause of death were considered. Styrene, butadiene, and benzene concentrations were all well within existing standards; mean concentrations at the two facilities were: styrene, 0.94 and 1.99 parts per million (ppm); butadiene, 1.24 and 13.5ppm; and benzene, 0.10ppm (only measured at one facility). Elevated ratios, though not statistically significant, were observed for the categories pertaining to malignant neoplasms of the lymphatic and hematopoietic tissues. For the subgroup of 600 workers, the standardized mortality ratio was significantly elevated for malignant neoplasms of the lymphatic and hematopoietic tissues and leukemia and aleukemia, with nonsignificant elevations for Hodgkin's disease and lymphosarcoma and reticulosarcoma. Length of employment did not correlate with cause of death. The authors conclude that production of this type of rubber may be associated with an excess of lymphatic and hematopoietic neoplasms.