Mortality patterns among workers exposed to styrene in the reinforced plastic boatbuilding industry: an update

Abstract

Background: Mortality was updated through 1998 for 5,204 workers exposed to styrene between 1959 and 1978 at two reinforced plastic boatbuilding plants. The a priori hypothesis: leukemia and lymphoma excesses would be found.

Methods: Standardized mortality ratios (SMR) and 95% confidence intervals (CI) used Washington State and U.S. rates.

Results: Overall, 860 deaths occurred (SMR 1.09, CI 1.02-1.17), with excess mortality for esophageal cancer (n = 12, SMR 2.30, CI 1.19-4.02), prostate cancer (n = 24, SMR 1.71, CI 1.09-2.54), and accidents (n = 99, SMR 1.26, CI 1.02-1.53). Among 2,062 highly exposed workers, urinary tract cancer (n = 6, SMR 3.44, CI 1.26-7.50) and respiratory disease (n = 12, SMR 2.54, CI 1.31-4.44) rates were elevated. Urinary tract cancer SMR increased with duration of employment.

Conclusions: We found no excess leukemia or lymphoma mortality. Unanticipated excess urinary tract cancer and respiratory disease mortality, possibly associated with styrene exposure, are difficult to interpret and could be chance findings.