Mortality study of employees in a factory of recovery and refining of catalytic converters in Rome, Italy.

The study objective is to describe cause specific mortality of employees in a plant engaged in production, recovery and refining of catalytic converters located in Rome. Previous epidemiological studies conducted in similar plants are not available. A total of 828 workers (642 males and 186 females) were followed up between 1956 and 31-12-2003. Cause specific standardized mortality ratio (SMR) and 90% confidence intervals (CI) were computed using regional rates for comparison. Among males hired between 1956 and 1993, followed up until 31/12/2003, mortality for all causes (SMR 0,8; 90% CI 0,7-1,0; 85 observed) and all neoplasms (SMR 0,6; 90% CI 0,42-0,87; 20 observed) is below expected; an increase is present for liver cirrhosis (SMR 2,74; 90% CI 1,47-5,1; 7 observed) and brain cancer (SMR 5,24; 90% CI 2,3-11,90; 4 observed). The present investigation complies with the proposed scientific standards for occupational cohort studies. The study was not prompted by well defined a priori hypotheses but it is included in a process intended to typify a potentially polluted site; the absence of a priori hypotheses and of previous epidemiological evidence, prevent from a causal interpretation of the increased mortality from liver cirrhosis and brain cancer. The implementation of cohort studies in industrial sites where industrial activities similar to the one here examined are present, are highly recommended.