A study of mortality due to lung cancer in workers exposed to sulfuric-acid (7664939) mist and other acid mists was conducted. The cohort consisted of 1165 individuals employed for at least 6 months in pickling related jobs between 1940 and 1965 at three midwestern steel manufacturing facilities. Each pickling related job was categorized as to whether the acid used was sulfuric-acid or another acid and the likelihood of daily exposure to acid mist. Vital status of the cohort as of October 27, 1981 was determined. Standardized mortality ratios (SMRs) were calculated using the United States (US) general population and a population of 51,472 white male workers at seven steel manufacturing facilities in Allegheny County, Pennsylvania. A total of 326 deaths had occurred in the cohort, versus 334.4 expected in the general US population. Seventy three deaths due to cancer occurred, versus 66.1 expected. A significantly increased risk of lung cancer was observed, with 35 deaths compared to 21.3 expected in the general population. This yielded a SMR of 1.64 for workers exposed to any acid mist. When exposure to only sulfuric-acid mist was considered the lung cancer SMR was 1.39. The lung cancer SMR for workers who had daily exposure to sulfuric-acid was 1.58. The lung cancer SMRs were substantially higher 20 years after first exposure. Except for deaths due to diabetes mellitus, no other significantly elevated cause specific mortality occurred. There was a significant deficit in deaths from digestive system diseases. When the Allegheny County steel workers were used as comparison, lung cancer mortality was significantly elevated only for pickling workers exposed to acids other than sulfuric-acid, with a SMR of 2.00. Estimated SMRs for lung cancer due to smoking were 1.06 to 1.24. The authors conclude that there is an increased risk of lung cancer in steel pickling workers exposed to acid mists and that the increased risk is not due to smoking.