A case-control study of residents who lived in the vicinity of a primary zinc smelter and a large steel manufacturing plant in eastern Pennsylvania was undertaken to investigate the role of environmental pollutants in the etiology of lung cancer. Lifetime residential, occupational, and smoking histories were obtained from the next of kin of 335 white male lung cancer cases and 332 white male controls. Soil samples were collected and analyzed for content in ppm of arsenic, copper, lead, manganese, zinc, and cadmium. Relative risks were determined according to distance of residence from the zinc smelter and the steel plant, and according to residence in areas with heavy and light levels of various pollutants. Two-fold risks for lung cancer were associated with residence near the zinc smelter and with residence in areas with heavy levels of arsenic and cadmium, although the number of individuals living in these higher risk areas was small. These increases were not explained by the effects of cigarette smoking or by employment in the zinc or steel industry. No excess risk was associated with living near the steel plant. The limited size of the study precludes causal interpretation, but the findings suggest the need for further investigation of metallic air pollution and lung cancer.