MORTALITY, MORBIDITY, AND HEMATOLOGICAL RESULTS FROM A COHORT OF LONG-TERM WORKERS INVOLVED IN 1,3-BUTADIENE MONOMER PRODUCTION

A retrospective mortality analysis and prospective morbidity and haema tological analyses were performed for Shell Deer Park Manufacturing Co mplex (DPMC) male employees who worked in jobs with potential exposure to 1,3-butadiene from 1948 to 1989. 614 employees qualified for the m ortality study (1948-89), 438 of those were still employed during the period of the morbidity study (1982-9), and 429 of those had haematolo gical data available for analysis. Industrial hygiene data from 1979 t o 1992 showed that most butadiene exposures did not exceed 10 ppm (eig ht-hour time weighted average (8 hour TWA)), and most were below 1 ppm , with an arithmetic mean of 3.5 ppm. 24 deaths occurred during the mo rtality study period. For all causes of death, the standardised mortal ity ratio (SMR) was 48 (95% confidence interval (95% CI) = 31-72), and the all cancer SMR was 34 (95% CI = 9-87). There were only two deaths due to lung cancer (SMR 42, 95% CI = 5-151) and none due to lymphohae matopoietic cancer (expected = 1.2). Morbidity (illness absence) event s of six days or more for the 438 butadiene employees were compared wi th the rest of the complex. No cause of morbidity was in excess for th is group; the all cause standardised morbidity ratio (SMbR) was 85 (95 % CI = 77-93) and the all neoplasms SMbR was 51 (95% CI = 22-100). Hae matological results for the 429 with laboratory data were compared wit h results for the rest of the complex. No significant differences occu rred between the two groups and the distributions of results between b utadiene and non-butadine groups were virtually identical. results sug gest that butadiene exposures at concentrations common at DPMC in the past 10-20 years do not pose a health hazard to employees.