Extrapolation of the Benzene Inhalation Unit Risk Estimate to the Oral Route of Exposure (External Review Draft)
Notice - This site contains archived material(s)
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 The file was current when produced, but is no longer maintained and may now be outdated.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 use the contact us form if you need additional support.
Given the absence of oral dose-response information, the authors propose a simple method for extrapolating benzene-induced cancer risk from the inhalation to the oral route. The method is based on the relative efficiency of benzene absorption across pulmonary and gastrointestinal barriers. Substantial literature on pulmonary absorption in humans and a few laboratory animal species exists. Data on oral absorption in humans are lacking; hence extrapolation is based on gastrointestinal absorption studies in several experimental animal species. A review of the relevant literature suggests absorption efficiencies of 50% and 100% for inhalation and oral routes of exposure, respectively. Application of these absorption factors to the current inhalation unit risk range of 2.2 X 10
This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.