US EPA

EPA's assessment of the carcinogenic potential of 1,1,1-trichloroethane was entered into the IRIS database in 1988, and the assessment of noncancer effects following oral exposure was withdrawn from IRIS in 1991. The IRIS program prepared an update of the IRIS assessment for 1,1,1-trichloroethane, which incorporated health effects information published since the last assessment was prepared as well as new risk assessment methods.

The IRIS assessment for 1,1,1-trichloroethane consists of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physicochemical and toxicokinetic properties of the chemical and its toxicity in humans and experimental systems. The assessment presents reference values for the noncancer effects of 1,1,1-trichloroethane (Reference Dose and Reference Concentration), and a cancer assessment. The Toxicological Review and IRIS Summary were subject to internal peer consultation, Agency review, Interagency review, and external scientific peer review. The final products constitute the Agency's opinion on the toxicity of 1,1,1-trichloroethane. The assessment of 1,1,1-trichloroethane also served as a pilot for the implementation of certain health assessment procedures proposed in the 2002 report, "A Review of the Reference Dose and Reference Concentration Processes," prepared by the Risk Assessment Forum's Reference Dose/Reference Concentration (RfD/RfC) Technical Panel. Included in this pilot was the implementation of recommendations related to the development of toxicity values for less-than-lifetime exposure, the presentation of study findings in tabular and graphical formats, and the use of a weight-of-evidence approach for characterizing the potential for noncancer effects in exposed populations.

EPA prepared an update of the Integrated Risk Information System (IRIS) health assessment for 1,1,1-trichloroethane. The outcome of this project was an updated Toxicological Review and IRIS Summary of 1,1,1-trichloroethane that was entered on the IRIS database in September 2007. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effects that may result from exposure to chemicals in the environment. IRIS contains chemical-specific summaries of qualitative and quantitative health information in support of two steps of the risk assessment process, i.e, hazard identification and dose-response evaluation. IRIS assessments are used nationally and internationally in combination with specific situational exposure assessment information to evaluate potential public health risks associated with environmental contaminants. The IRIS database is relied on for the development of risk assessments, site-specific environmental decisions, and rule making.

U.S. EPA. IRIS Toxicological Review and Summary Documents for 1,1,1-Trichloroethane (Peer Review Plan).