The Office of Health and Environmental Assessment of the Office of Research and Development, Environmental Protection Agency (EPA), has prepared this health assessment to serve as a "source document" for EPA use. While the assessment was originally initiated for use in evaluating chloroform as a toxic air pollutant under provisions of Section 112 of the Clean Air Act, the scope of the assessment covers other exposure pathways such that it is useful to other media-specific programs in the EPA. In the development of the assessment document, the scientific literature has been inventoried, key studies have been evaluated, and conclusions have been prepared in order to qualitatively and quantitatively identify the toxicity of chloroform. Toxic effect exposure levels and other measures of dose-response are discussed, where appropriate, to place the nature of the health responses in perspective with chloroform levels in the environment. Information regarding sources, of chloroform release to the environment, emissions, ambient air concentrations, and public exposure has been included only to give the reader a preliminary indication of the potential presence of this substance in the environment. While the available information is presented as accurately as possible, it is acknowledged to be limited and dependent in many instances on assumption rather than specific data. This information is not intended, nor should it be used, to support any conclusions regarding risks to public health.