Respiratory disease mortality among workers employed at selected crushed stone mining and milling operations in the period 1940 through 1980 was evaluated. The sample group included 20 operations (nine limestone, six granite, and five traprock) and 5,807 workers; the final analyzed cohort consisted of 3,246 men with more than 1 year of tenure. Pneumoconiosis contributed to at least four deaths in this group; at least two of these deaths were apparently due to dust exposures in the crushed stone industry. Twenty workers had an underlying cause of death classified as pneumoconiosis and other respiratory diseases. Causes of death included chronic obstructive lung disease, chronic interstitial pneumonia, silicosis, lung abscess, and empyema. Mortality attributed to respiratory diseases was significantly increased overall, especially for a subcohort of crushed stone workers that processed granite. Overall standardized mortality rates (SMRs) were slightly elevated for lung cancer; there was, however, a significantly elevated lung cancer SMR for granite workers with at least 20 years latency. The authors conclude that the findings of this study are consistent with the hypothesis that exposure to respirable silica (14808607) dust is a risk factor for lung cancer in humans.