Petroleum refinery workers are potentially at risk of lymphoma and other cancers from exposure to benzene concentrated during the refining process. There have been many studies of workers in this industry, most of which have been conducted by industry-funded research groups. We identified 26 studies of petroleum refinery workers reporting morbidity or mortality for lymphomas and all (combined) neoplasms (Table 2 ). Lymphoma mortality or morbidity is significantly elevated in a few studies, but in most studies the rates are slightly but not significantly elevated. These slightly elevated rates, however, are striking because the studies report the population to have a deficit of mortality or morbidity from all (combined) neoplasms or all causes. Deficits in mortality and morbidity in cohorts of workers are often identified as the “healthy-worker effect.” The healthy-worker effect, however, would predict that the workers experience deficits in mortality and morbidity from all causes: morbidity and mortality rates near those experienced by the general population or white-collar workers are suggestive of adverse health effects from occupational exposures. Among the 26 studies reporting mortality or morbidity from all neoplasms and from NHL, 23 (88%) showed that the rate of lymphoma morbidity or mortality was higher than that for all neoplasms. A similar trend appears for studies reporting all-cause mortality: the rate of lymphoma mortality is greater than the rate of all-cause mortality in 14 of 17 (82%) of studies reporting both outcomes.