This genetic toxicology testing contract has supported the overall mission of NTP to provide detailed toxicological profiles, including potential for carcinogenicity, of compounds of interest for over 30 years. Assessment of genetic damage, an important factor in the initiation and development of cancer as well as neurodegenerative diseases such as ALS, neurological conditions such as autism, aging processes, birth defects such as Down syndrome, mitochondrial diseases, and other adverse human health effects, is a critical component of any in-depth toxicological profile of a chemical or product. An important complication in assessing the impact of environmentally induced genetic damage is that genetic damage induced early in life, even prior to birth, may not manifest as an adverse health effect until decades later, during adulthood. This delay in manifestation, along with a lack of any immediate symptoms of genetic damage, makes it difficult to link early life exposures that cause genetic damage with adult disease. Because of the importance in understanding potential for induced genetic damage, a detailed characterization of the genotoxic potential of new pharmaceutical and pesticide products, as well as other types of products for which human exposure is a concern, is required by regulatory agencies such as the Food and Drug Administration and the Environmental Protection Agency prior to approval for use. This Genetic Toxicity Testing contract provides information to the NTP on various types of exposure-related genetic damage using universally accepted standard testing protocols as well as innovative approaches, when necessary and applicable, to supplement the information obtained from standard tests. Testing systems employed under this contract include both in vitro (animal and human cell-based, and bacterial) and in vivo (rats and mice) assays. The capabilities of this genetic toxicity testing contract are continuously updated to remain current with the latest scientific approaches in the field and consistent with international guidelines for conducting these kinds of tests. The field is currently undergoing rapid evolution with the many dramatic changes in technological capabilities that are occurring today.