IRIS Toxicological Review of Benzene (Noncancer Effects)
Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the NCEA Webmaster for assistance. Please visit http://epa.gov/ncea to access current information.
Benzene, also known as benzol, is widely used as an industrial solvent, as an intermediate in chemical syntheses, and as a component of gasoline; hence, the potential for human exposure is great. The emphasis of this document is a discussion of the noncancer adverse health effects of benzene including the no-observed-adverse-effect levels, the lowest-observed-adverse-effect levels, benchmark dose analysis, uncertainty factors, and any other considerations used to develop the reference dose (RfD) and reference concentration (RfC) for benzene.
The Toxicological Review concludes that chronic benzene exposure may pose several types of noncancer human health hazards. Hematotoxicity, e.g., progressive deterioration of hematopoietic function, has been consistently reported to be the most sensitive indicator of noncancer toxicity in both experimental animal studies and occupationally exposed humans. The hazards can result from inhalation, oral or dermal exposure, though the exposure circumstances vary. The Toxicological Review includes estimates of chronic exposure levels for oral exposure (RfD) and inhalation exposure (RfC) that are thought to be without appreciable risk.