The major issue addressed in this document involves the nature and magnitude of the risk of cancer to humans exposed to low levels of benzene.
Occupational studies continue to provide the bulk of evidence of benzene's carcinogenicity.
Workers are exposed at much higher levels than is the general public. This document verifies that benzene is a known human carcinogen by all routes of exposure. Human epidemiologic studies of highly exposed occupational cohorts have demonstrated that exposure to benzene can cause acute nonlymphocytic leukemia and other blood disorders, that is, preleukemia and aplastic anemia. Additionally, changes in blood and bone marrow consistent with hematotoxicity are recognized in humans and experimental animals. Because this knowledge is not available at the present time, the Agency's approach of using a model with low-dose linearity is still recommended.