Mortality, morbidity, and haematological results from a cohort of long-term workers involved in 1,3-butadiene monomer production.

Abstract

A retrospective mortality analysis and prospective morbidity and haematological analyses were performed for Shell Deer Park Manufacturing Complex (DPMC) male employees who worked in jobs with potential exposure to 1,3-butadiene from 1948 to 1989. 614 employees qualified for the mortality study , 438 of those were still employed during the period of the morbidity study , and 429 of those had haematological data available for analysis. Industrial hygiene data from 1979 to 1992 showed that most butadiene exposures did not exceed 10 ppm (eighthour 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 mortality study period. For all causes of death, the standardised mortality 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 lymphohaematopoietic cancer (expected = 1.2).Morbidity (illness absence) events of six days or more for the 438 butadiene employees were compared with the rest of the complex. No cause of morbidity was in excess for this 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). Haematological results for the 429 with laboratory data were compared with results for the rest of the complex. No significant differences occurred between the two groups and the distributions of results between butadiene and non-butadiene groups were virtually identical.These results suggest that butadiene exposures at concentrations common at DPMC in the past 10-20 years do not pose a health hazard to employees.

Epidemiology of environmental and occupational cancer

“…This study showed a clear increased risk of leukaemia, based on 58 deaths, with a dose-response (RRs 1.0 (reference group), 1.5 (95% CI 0.7-3.2) and 1.7 (95% CI 0.8-3.9) in the three categories of increasing butadiene exposure; P-value of test for linear trend 0.03), which was not explained by exposure to styrene or other agents. These results receive a limited support by the only other large cohort study conducted Environmental and occupational cancer P Boffetta among butadiene production workers (Divine and Hartman, 1996), while no clear excess was present in the remaining, smaller studies (Bond et al, 1992;Cowles et al, 1994;Ward et al, 1996). Overall, the presence of a causal association between butadiene exposure and occurrence of cancer (leukaemia in particular) in humans is plausible: this conclusion is supported by a single large and very carefully conducted study and is compatible with the results of an additional valid, although less informative, study.…”

Mortality from cancer and other causes of death among synthetic rubber workers.

“…Utility workers are employed in power generation and in water supply and treatment operations and would have had low exposure to monomers. Meinhardt et al 5 22 did not provide data on laryngeal cancer. Divine et al 6 found slightly more than expected deaths from laryngeal cancer in some subgroups of butadiene production plant workers, but the results were based on small numbers.…”

Aliphatic Hydrocarbons

“…Men entered the study if they had been employed for at least 5 years in jobs with potential exposure to butadiene. There were no deaths due to cancer of the lymphatic and hematopoietic tissue (540). In the most recent follow-up, three deaths due to cancer of the lymphatic and hematopoietic tissues were observed (SMR ¼ 1.1; 95% CI, 0.3-1.5), and no deaths from leukemia were observed, whereas one death was expected (552).…”