The source documents for background information used to develop the report on the quantification of toxicological effects for dichloromethane are the health assessment document (HAD) for dichloromethane and a subsequent addendum to the HAD (U.S. EPA, 1985b). In addition, some references published since 1985 are discussed. To summarize the results of the quantification of toxicological effects, a One-day Health Advisory of 10,000 ug/L for a 10-kg child was calculated, based on an acute oral study in rats reported by Kimura et al. (1971). No suitable data for the derivation of a Ten-day Health Advisory were found in the available literature.