Mortality among workers at a plastics manufacturing plant

Abstract

KEY WORDSThis study evaluated the 1970-1993 mortality experience of 2550 of white and mortality black men employed at a Texas plastics plant that made polyethylene, polyplastics manufacturing propylene, K-resin (a copolymer of 1,3-butadiene and styrene) and other occupational epidemiology materials. Of particular interest was the relationship between work in plastics manufacturing and colorectal cancer, as certain epidemiological investigations have reported an increase in this form of cancer among workers with potential exposure to polypropylene. Overall, subjects had fewer than expected deaths from all causes combined (269 observed/364.3 expected), from all cancer (79/89.3) and from colorectal cancer (5/9.5). Polypropylene workers had one observed compared with 0.4 expected death from colorectal cancer. A two-fold increase in deaths from accidents among hourly men was attributable to an explosion in the polyethylene area. Certain subgroups of workers had a slight increase in lung cancer deaths. These results were not statistically significant, did not display marked patterns with duration of employment or time since hire and were not clearly attributable to occupational exposure. Some subgroups of employees had more than expected deaths from oesophagus cancer, pancreas cancer and prostate cancer. These findings were based on small numbers, and there is no persuasive evidence that the excesses were due to chemicals at the plant. However, longer follow-up will be necessary to obtain more precise results for subjects with longterm employment and with long potential induction time.