This study examines the cause-specific mortality of men employed as masons in the steel industry. Their mortality experience is compared with the mortality predicted by the age--and race--specific death rates for a control group consisting of those steelworkers whose first job in 1953 was not in the mason department. The relative risks of dying from selected causes were highly dependent on race. The most important observations are: (1) The nonwhites have an overall excess risk when compared to the nonmason group. This excess is not confined to any particular category and appears to be due to the cumulative effect of an excess in many different categories. (2) The white masons have an excess risk for nonmalignant respiratory disease. Furthermore, this risk increases with length of exposure. (3) The whites have an excess risk for respiratory cancer when compared to the nonmason group. This excess is not present in the later years of the follow-up period. (4) The interpretation of the findings for cardiovascular disease remain unclear. Results for cerebral vascular disease and hypertensive disease in nonwhites are suggestive, but need further investigation before any strong statements can be made.