This paper reviews the epidemiologic evidence of cancer risks among workers in aluminum reduction plants with emphasis on associations with specific work areas and exposures. Studies of workers manufacturing carbon products outside the aluminum industry were also reviewed since the work environment is similar to that encountered in the carbon area of aluminum plants. We obtained 22 reports from references cited in earlier reviews, through compact disc literature search 1980-1990, and from the Nordic Aluminum Industry's Secretariat for Health, Environment and Safety. Six reports were excluded because the material was included in later studies or because a critical evaluation was impossible. This left 16 publications from 11 separate studies. Work in potrooms with Söderberg electrolytic cells was associated with increased risk of bladder cancer, and the increase was correlated to duration of tar exposure. There was a suggestion of increased risk of leukemias and pancreatic cancers in potroom workers, and of kidney and brain cancers without any clear association with specific exposures or work areas. Singular results showed associations between lung cancer risk and tar exposure in Söderberg plants, and between lung cancer and work in prebake or carbon plants, but interpretation was limited by inadequate data on smoking and asbestos exposure, and by problems connected with the choice of reference populations in these studies.