Objective of this study was to assess the mortality experience of a cohort of chemical workers at a plant located in central Italy. Subjects employed for any time between 1954 and 1970 at the chemical plant were included in the cohort and followed up to June 1991. The workers were classified as having ever/never worked in one of the following work processes: organic chemicals, acid mixtures, cleansing agents and insecticides. Mortality experience of the cohort was compared with that of the regional population by computing SMRs (standardized mortality ratios) and 90% CI (confidence intervals). Vital status was ascertained for 96% of the 505 cohort members. All causes of mortality for the entire cohort were lower than expected (Obs: 176; SMR: 0.90; 90% CI: 0.79-1.03). Analysis by work process revealed an increased mortality for lymphatic and hematopoietic tissue neoplasm in the cleansing agents department (Obs: 3; SMR: 5.00; 90% CI: 1.36-12.9); peritoneum and retropertioneum neoplasm in the organic compounds production (Obs: 2; SMR: 13.33; 90% CI: 2.37-42.0), and bladder cancer in the insecticides process (Obs: 3; SMR: 3.53; 90% CI: 0.96-9.12). Although the study had a low statistical power, the increased cancer risks detected are consistent with previous observations and may be of etiologic interest.