Mortality study in an Italian oil refinery: Extension of the follow-up

This article present the results of the extension of the follow-up of a coh ort of workers employed in an Italian oil refinery 1,583 workers employed i n 1949-1982 in a northern Italy oil refinery plant were followed-up for mor tality as of May 31, 1991. Environmental measurements documented potential exposure to benzene. Standardized mortality ratios (SMR) and their 95% conf idence intervals (95% Cl)were calculated using as references national (1949 -1968) and regional mortality rates (1969-1991). Elevated mortality from ly mphoma (seven deaths, SMR 190, 95% CI 76-391) and leukemia (eight deaths, S MR 225 95% CI 97-443) was observed No consistent trend by length of employm ent or time since first exposure were apparent. Nonetheless, the excess ris k was particularly and significantly increased among workers with 15 or mor e years of employment, and 30 or more years since first employment. The fin dings of elevated mortality from leukemia and lymphoma are in agreement wit h those of other oil refinery studies. Chance, confounding, or other biases might have played a marginal, if any, role in determining the results. Exp osure to benzene is a biologically plausible explanation. (C) 1999 Wiley-Li ss, Inc.