Interim procedures for estimating risks associated with exposures to mixtures of chlorinated dibenzo-p-dioxins and-dibenzofurans (CDDs and CDFs) and 1989 update

Abstract

In 1987, the U.S. Environmental Protection Agency (EPA) formally adopted an interim toxicity equivalency factor (TEF) procedure (see PB89 125041), which has been used in addressing a variety of situations of environmental contamination involving CDDs and CDFs. The method, published as Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and -Dibenzofurans (CDDs and CDFs), is republished as Part I of the document. Since the 1987 report was published, the EPA has been active in an international project aimed at adopting a common set of TEFs, the International TEFs/89 (I-TEFs/89), to promote consistency in addressing contamination involving CDDs and CDFs. The 1989 Update to the Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and -Dibenzofurans (CDDs and CDFs) identifies EPA's adoption of the I-TEFs/89 as a revision to the method currently in use. The 1989 Update is Part II of the document.