Benzene-contaminated toluene and acute myeloid leukemia: a case series and review of literature.

We report seven cases of acute myeloid leukemia (AML) with occupational exposure to a toluene-based hydrocarbon solvent. The cases were employed at a facility, which manufactured rubber belts and hoses, between 1950 and 2005 for periods ranging from 21 to 37 total years. Detailed histories were obtained for three workers who were diagnosed with AML within a 3-year period (2003-2005). Death certificates, medical records, and accounts by workers were reviewed. Benzene, a known cause of AML, is typically a contaminant of toluene. Benzene contamination in toluene and other widely used solvents and the potential for concurrent benzene exposure during usage of these solvents in occupational settings are discussed.