An effort was made to integrate industrial hygiene studies and chemical analyses with inhalation toxicology experiments in order to identify the pulmonary hazards that may arise from an oil shale industry. Results indicate that raw shale dusts cause very little epithelial or fibrotic reaction. Retorted shales elicit inflammatory reaction with varying degrees of fibrosis and epithelial hyperplasia. The shale dusts appear as agglomerations rather than as individual particles, with a peribronchiolar pattern. The chemical availability of total hydrocarbons and polycyclic aromatics varies inversely with particle size
