The Toxic Substances Control Act of 1976 (15 U.S.C. §2601 et seq.) authorizes the U.S. Environmental Protection Agency (EPA) to promulgate and enforce rules on chemical substances in commerce. Section 8 (a) of the law requires the EPA to collect basic exposure-related information on the types, quantities and uses of chemical substances produced domestically and imported into the United States.Called the Chemical Data Reporting Rule (CDR) [40 CFR Part 711], this information is collected every four years from manufacturers producing or importing more than 25,000 pounds of chemicals; however, a small number of chemicals subject to certain TSCA actions will have a reporting threshold of 2,500 pounds.