Benzene and Leukemia: What Are the Risks and What Do the Data Reveal?

Abstract

Although benzene exposure is recognized as a risk factor for leukemia, there is still no universal consensus regarding which leukemias and what degree of exposure. Definition of benzene-associated leukemia has become more specific as the classification of leukemias is better understood. Review of the studies of benzene-exposed workers finds the excess of leukemia to be generally limited to acute myelogenous leukemia and its variants. Exposure assessment in these analyses has also become more sophisticated. The earliest risk assessments assumed that past exposures were at the legal limit; later analyses considered the exposure data available at the worksite studied. The most recent analyses have focused on the lifetime benzene exposure history of the employees studied, extending beyond the exposure at the studied worksite. Sub-analyses suggest that critical factors included level of exposure, rather than just cumulative exposure. The quality of risk analysis is enhanced when more complete information on exposure is included.