The risk of specific types of leukemia in coal miners (SIC-1211) due to different electrical and magnetic fields was analyzed. A population of 19,000 coal miners was examined and 40 miners with International Classification of Diseases codes 204 through 207 were identified. Each of the 40 white male leukemia patients was matched by age at death and year of birth to 4 comparisons from the same cohort who died of other causes. Number of years mining and smoking status and pneumoconiosis were examined. Smoking and pneumoconiosis were not related to leukemia risk for miners. However, there was a 2.5 fold increase in leukemia risk for miners who have worked underground for more than 25 years. Over 25 percent (11 cases) of the leukemia cases were classified as chronic lymphatic leukemia, and 14 cases were classified as acute myelogenous leukemia. The authors conclude that prolonged underground miner exposure brings increased risk of leukemia to white males. Multiple exposures, such as to benzene (71432) used in degreasing, could explain the elevated acute myelogenous risk. It is suggested that since chronic lymphocytic leukemia has not been linked to chemical exposure, radiation, or other environmental agents (except electrical), a possible relationship may exist between electromagnetic field exposure in mines and this form of leukemia.