The results of an extension of follow up (1976 to 1989) of a cohort of workers employed for at least one year between 1 January 1950 and 31 December 1975 at eight oil refineries in Britain are reported. Over 99% of the workers were successfully traced to determine their vital status at 31 December 1989. The mortality observed was compared with that expected from the death rates of all the male population of England and Wales and Scotland. The mortality from all causes of death for the total study population was lower than that of the comparison population, and reduced mortality was also found for many of the major non-malignant causes of death. Raised mortality patterns were found for diseases of the arteries, in particular aortic aneurysm, and accidental fire and explosion, for the total study population, and across several refineries and other subgroups. Mortality from all neoplasms was lower than expected overall, largely due to a deficit of deaths from malignant neoplasm of the lung. Raised mortality from all neoplasms was found for labourers and in particular for malignant neoplasms of the oesophagus, stomach, and lung, although the mortality was also high for all men in this social class in the national population. Regional variations may have accounted for some of the high mortality. There were other raised mortality patterns in malignant neoplasms of the intestine, rectum, larynx, and prostate but these tended to be isolated and not consistent across refineries and other subgroups. As in the earlier follow up there was raised mortality from melanoma in several job groups.