High Quality Content by WIKIPEDIA articles! The Toxic Substances Control Act (TSCA) is a United States law, passed by the United States Congress in 1976, that regulates the introduction of new or already existing chemicals. It grandfathered most existing chemicals, in contrast to the Registration, Evaluation and Authorization of Chemicals (REACH) legislation of the European Union. However, as explained below, the TSCA specifically regulates polychlorinated biphenyl (PCB) products.