A survey of mortality in metal miners was conducted. The cohort consisted of 12,258 non uranium miners who were previously examined by the United States Public Health Service as part of a survey of silicosis. Standardized mortality ratios (SMRs) were calculated by means of a life table procedure. To narrow the causative factors in cases in which statistically significant increases in SMRs were seen in the mortality study, 163 cases of cancer of the trachea, bronchus, and lung were matched one for one or two for one to workers who died from all causes except cancer of the trachea, bronchus, and lungs. The metal miners showed statistically significant increases in SMRs for all causes, respiratory cancer, nonmalignant respiratory disease, and accidents. Significant decreases in digestive cancer and hypertensive heart disease mortality occurred. Lead/zinc, mercury, and chrome miners showed significant increases in SMRs for lung cancer. This was confirmed by the case control study. The case control study indicated an increased risk for lung cancer in gold and silver miners. Smokers showed significant increases of SMRs for all causes, all cancers, diseases of the respiratory system, and accidents. In the case control study, smokers showed relative risks for lung cancer of 2.7 in the one for one and 2.2 in the two for one match. Nonsmokers showed significant decreases in SMRs for all causes, all cancers, and circulatory system disorders. Underground face workers had the greatest number of increased SMRs, followed by underground transportation workers, maintenance workers, miscellaneous workers, and surface workers. Airways obstruction as a causative factor in lung cancer showed an increased relative risk of 1.3 to 1.4. Exposure to diesel fumes had a relative lung cancer risk of 1.5 in the one for one, but not the two for one match.