[Mortality in an Italian factory producing tetraethyl lead]

The Società Lavorazioni Organiche Inorganiche (SLOI) in Trento (North-Eastern Italy) produced tetraethyl lead from 1941 to 1978, when it was closed following an explosion, luckily with no fatalities. Working conditions were very bad. During the 1960s, 325 acute lead intoxications were reported and over 100 workers were hospitalized for neurological conditions attributable to tetraethyl lead. At least 12 SLOI workers were hospitalized in the mental asylum (psychiatric wards).The present work describes the first formal epidemiological study ever carried out on SLOI workers. In the absence of any original SLOI employee registers, a list of 1,742 workers hired since factory startup was assembled using the files of the Italian National Social Security Agency (digitalized in 1974 and perused manually by one of the Authors for the previous period). To date, follow-up for mortality has been completed for the 580 male employees at work in 1961 or hired subsequently and who worked at SLOI for at least 12 months. Twenty-two (3.8%) were lost to follow-up. Mortality in this sub-cohort was compared with that of the population of the province of Trento, gathered since 1986 by the Institute of Statistics of the Trento Province. Excluding deaths occurring at age 90+ years, during the 1986-2016 period, deaths in the SLOI sub-cohort were 295 vs 229.0 deaths expected from age- and period-specific rates in the reference population (standardazied mortality ratio 1.29; 95%CI 1.15-1.44). In the absence of individual data, the possible contribution to the mortality excess by non-occupational risk factors cannot be estimated. Identification of causes of death is underway.