Recognizing the pervasive environmental presence of an increasingly large number of chemical substances, Congress passed the Toxic Substances Control Act (TSCA)¹ in late 1976 to impose a federal regulatory scheme over substances that present an unreasonable risk of injury to human health and the environment. This scheme includes the mandatory collection of data on those substances currently being used and the hazards they present, followed by vigorous regulation of the manufacture and use of dangerous substances in order to minimize or eliminate those hazards. Because of the ubiquitous presence of chemical substances, the enormous role they play in everyday life, and the delays that seem to be inherent in beginning a large government regulatory program, the development of regulations to implement TSCA's complex requirements has proved a lengthy process. In addition to difficulties in determining who should be covered by the regulations and what substances should be reported, the unexpectedly controversial issue of how best to maintain the confidentiality of the reported information served to delay the promulgation of TSCA regulations. The Environmental Protection Agency (EPA), however, has recently taken the first significant steps in establishing what will become, along with air and water pollution regulation, one of the major national programs for environmental protection.