US EPA

This article reviews all of the relevant information on propylene oxide including physical and chemical properties, environmental fate and transport processes, exposure (water, food, inhalation and derital), pharmacokinetics, effects (carcinogenicity, mutagenicity, teratogenicity, other reproductive effects and chronic toxicity), aquatic toxicity, existing guidelines and standards, and develops risk assessments. The available toxicological data regarding propylene oxide indicate that the compound is a contact carcinogen in rodents, causing forestomach tumors following ingestion and nasal tumors after inhalation exposure. The lack of data on humans exposed to propylene oxide precludes an evaluation of its carcinogenicity for humans; however, the U.S, EPA's Carcinogen Assessment Group considers propylene oxide a possible human carcinogen with a cancer potency value (q1*) of 1.31 x 10-2(mg/kg/day)-1 from mouse inhalation data, Applying the cancer guidelines, propylene oxide is most appropriately classified as a group 82 chemical. The Reportable Quantity (RQ) ranking based on chronic toxicity is 1000 from inhalation exposure.

Meylan, W., L. Papa, C. DeRosa, AND J. Stara. CHEMICAL OF CURRENT INTEREST PROPYLENE OXIDE: HEALTH AND ENVIRONMENTAL EFFECTS PROFILE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-86/502 (NTIS PB89201933).

Toxicology and Industrial Health, 2(3):219-260, 1986