In an update of an earlier investigation of brain tumors, mortality patterns were examined for 7,849 male employees who worked at a petrochemical plant from 1941 through 1983. The update added six years of observation (1978-83). During this period, the brain tumor (BT) mortality risk declined relative to the U.S. population, but continued to be higher than expected in hourly workers (5 obs./3.4 exp.). Similar to the earlier studies, BT occurrence was not explained by patterns of production work assignments. Mortality rates for hourly and salaried workers from all causes combined, total cancer and respiratory cancer were lower than U.S. population rates. Lower rates for these causes were also seen for white and nonwhite production and maintenance workers. Liver cancer rates were greater than expected in white production workers (3 obs. /1.6 exp.) and included two men assigned more than forty years ago to vinyl chloride-related departments. Mortality rates due to malignant melanoma were elevated in white maintenance workers (5 obs. /2.0 exp.) and may be explained by heavy sun exposure in outdoor work.