Work histories of oil refinery employees and whether deaths from brain tumor, stomach, cancer, and leukemia were associated with particular work situations were examined. Records of 2132 deceased workers showed 37 deaths from brain tumor, 52 from stomach cancer, and 32 from leukemia. From records of work history, each subject was classified according to one of the following work situations: crude oil refining, lubricating oil refining (second step refining), treating processes, coking, grease production, utilities, maintenance and labor, receipt and movement, laboratory, motor transport, and other activities. A slight association was seen for leukemia risk among workers in the treating processes category, and stomach cancer risk was elevated among maintenance workers and workers exposed to lubricating oils and paraffin wax processing (second step refining). No strong associations between brain tumor risk and employment within specific work categories were found. The authors conclude that no associations may have been found because of limitations of occupational categorizations, small numbers, or a true absence of elevated risk. Because the categories used were not exposure specific, workers exposed to particular chemicals may have had elevated risks of specific cancers regardless of the work categories assigned.