The purpose of this project is to identify and evaluate carcinogenic hazards of chemical and physical agents in the environment and to conduct research to improve methodology for carcinogenesis testing. For the most part the carcinogenesis test consists of using standardized long-term animal bioassays in which both sexes of two species are exposed to the agent for a major portion of its lifespan, i.e., 18-24 months. Usually two dose levels are used with extensive pathology examination performed on all animals. The majority of the actual testing is conducted with contracts with the Program staff responsible for developing the required resources, protocols, monitoring of progress and establishing methods of reporting results. Currently approximately 350 chemicals are on test using standard carcinogenesis tests. Detailed guidelines for testing as well as the first technical reports on test results have been published by the Government Printing Office.