The Toxic Substances Control Act (TSCA) Initial Inventory lists over 44,000 chemical substances (as defined by TSCA), identified by a preferred name and a unique Chemical Abstracts Service (CAS) Registry Number. Each preferred name (and, for some substances, an associated definition) identifies the composition of a chemical substance or category of chemical substances which has been manufactured, imported, or processed for a commercial purpose in the United States since January 1, 1975. All chemical substances appearing on the Initial Inventory, with the exception of 'naturally occurring substances' (as defined by the regulations), which are automatically included on the Inventory, have been identified from reports submitted to EPA by manufacturers and importers in response to the TSCA Inventory reporting regulations (40 CFR 710).

Issued May 1979. GPO Monthly Catalog entry number: 80-10119.

Volume 1. Initial inventory -- volume 2. User guide and indices to the initial inventory, Substance name index -- volume 3. User guide and indices to the initial inventory, Substance name index -- volume 4. User guide and indices to the initial inventory, Molecular formula and UVCB indices -- volume 5. Cumulative supplement 11 (1982).