The results of a study of mortality among firefighters based on surveillance data were summarized. Data contained in the National Occupational Mortality Surveillance System (NOMS) were searched to identify all deaths occurring among white male firefighters from 1984 to 1990. NOMS was a database maintained by NIOSH that encoded occupational data obtained from death certificates for 28 states. The database was created through collaboration between the National Center for Health Statistics, the National Cancer Institute, and the appropriate state health departments. Proportionate mortality ratios (PMRs) were computed by comparing the proportion of deaths from specific causes to all causes. A total of 5,744 deaths occurring among white male firefighters during the study period were identified. Mortality from all malignant neoplasms, accidental falls, and fire related accidents was significantly elevated, PMRs 110, 140, and 242, respectively. The excess cancer mortality was due to increased numbers of deaths from rectal, skin, kidney, lymphatic and hematopoietic cancers, nonHodgkin's lymphoma, and multiple myeloma, PMRs 148, 163, 144, 130, 132, and 148, respectively. Mortality from lung cancer, ischemic heart disease (IHD), and chronic obstructive lung disease (COPD), three diseases traditionally associated with fire fighting, was decreased, PMRs 102, 101, and 83, respectively. The authors conclude that the study supports the results of a previous study which found that firefighters do not have a high risk of mortality from lung cancer, IHD, and COPD. The lack of an observed increased risk for these causes of death could represent an excess occupational hazard superimposed upon a healthy worker effect.