This background paper was requested by the House Government Operations Committee and its Subcommittee on Intergovernmental Relations and Human Resources. In it, OTA describes policies issued by Federal agencies concerning the identification, assessment, and regulation of carcinogenic chemicals; the chemicals that have been regulated because of carcinogenic risk; the Federal Government’s carcinogenicity testing program; and the results of OTA’s analysis of the extent of agency action on chemicals determined to be carcinogenic.