Results of a mortality study of 3803 refinery and petrochemical workers at a U.S. facility are presented. Compared to national and local populations, significantly fewer deaths were observed for all causes combined, all malignant neoplasms, heart disease, nonmalignant respiratory disease, and cirrhosis of the liver among white male employees after 10 years or more latency. The brain cancer rate for this group was nonsignificantly increased; mortality from leukaemia was consistently lower than expected. Factors considered to contribute to this overall favourable mortality include the healthy worker effect, relatively low risks related to the workplace, and the beneficial effects of continuing employment.

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