Background On September 26th 1976 an accident occurred in a chemical plant located in Manfredonia (Apulia region, Italy) where Caprolactam (plastic) and Urea (fertilisers) were produced. More than 12 tons of arsenic compounds, used in the production of Urea, were released in the atmosphere, contaminating the plant and surrounding areas. Our study investigates late effects of arsenic exposure among workers present on the day of the accident and during the site clearance.

Methods We performed a historical cohort study including 1467 workers (39 females). Follow-up was performed by contacting municipalities of residence in Italy. Death certificates were collected. End of follow-up was either date of death, lost to follow-up or 15th March 2016. Cause specific mortality rates for the period 1976–2015 and 5 year age group were obtained for Apulia region and Foggia Province. Standardised Mortality Ratios will be calculated. Additionally, we will analyse data with Cox regression models by assigning workers to job category (white-collars, blue-collars and contract workers) and work area (fertiliser/plastic).

Results In the analysis restricted to men, we observed a total number of 51 102 person-years, 32 609 for 923 workers directly employed in the plant and 18 415 for 544 contract workers. We observed 307 deaths; 161 among contract workers. Highest mortality rate (8.7 deaths per 1000 person-year) was observed among contract workers. Higher values were observed among workers of the fertiliser work area.

Conclusions The results suggest an increased mortality for all causes among contract workers and employees in the fertiliser area. Cause-specific analysis will be presented.