Evaluations by a panel of industrial hygienists were used to classify occupational groups by degrees of exposure to airborne particulates, irritant gases, organic vapors, and temperature extremes. Data from 216 occupations and 75 categories of disability were examined. An index figure, the proportionate morbidity ratio (PMR), was calculated for each disabling condition in an occupation. The data indicated that occupations where particulate exposure was common had higher PMR's for emphysema. Chi-square tests (X2) were performed to test statistical significance. Four general hazard conditions were selected for the tests: organic vapors, irritant gases, particulates, and extremes of heat and cold. In the particulate hazard category, X2 for emphysema was 138.75 compared to only a 8.95 for lung cancer. Emphysema was also statistically significant in the irritant gases category where X2 was 82.68 and in the extreme heat and cold category where X2 was 84.82. Lung cancer was not statistically significant in any of the categories. Many of the 75 disease conditions (including cirrhosis of the liver, cancer of the digestive organs, and glaucoma) had negative Chi-square values for at least three of the four categories. The authors state that for many of the diseases and general hazard categories, reasons for the data reported can only be speculated; however, the data may have public health significance.