The subject contract provides support to Division of Translational Toxicology (DTT) hazard identification activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical or physical agents. The services provided under this pathology support contract are an integral component of the evaluation of pathology data generated by DTT studies and in ensuring the consistency and accuracy of that data. Most of the studies are toxicity studies aimed at elucidating the cancer-causing potential or other potential toxic effects of chemicals or agents. Other types of studies are also conducted, including immunotoxicity studies and reproductive and developmental toxicity studies. These studies are used to evaluate the effects of various chemicals or physical agents of public health concern. Pathology data generated in these studies are used by the DTT to prepare final technical and toxicity reports. These reports provide a direct benefit to the public since government regulatory agencies consult these reports when making regulatory decisions concerning the use of or exposure to chemicals or agents. Therefore, it is imperative that the data be complete and accurate, which underscores the importance of the pathology peer review services provided by this contract. The services provided by the Pathology Support Contract are also utilized to generate pathology data for NIEHS investigators at various stages during the conduct of laboratory-based research studies. This data is often used in the preparation of manuscripts and reports for publication in peer-reviewed scientific journals. Therefore, the specific aim of this contract is to continue to provide quality, professional pathology, histology, necropsy, and molecular biology/pathology services to the NTP/DTT and to NIEHS investigators.