Epidemiologic studies of Scottish oil shale workers: I. Prevalence of skin disease and pneumoconiosis

In an epidemiologic study of 6,359 oil shale workers, 1,664 (46.7%) of 3,566 survivors were investigated. No excess of skin disease (as reported in response to a questionnaire) was found in men exposed to oil or dust, whether compared to men who were not exposed to oil or dust or to coalminers. A low prevalence of simple pneumoconiosis was found in workers exposed to dust, while progressive massive fibrosis occurred in approximately 1% of miners and retort workers. Comparisons of responders with non-responders revealed no serious bias in terms of age or work experience, though non-responders were likely to have been less healthy in general.