The TSCA Chemical Substance Inventory provides chemical identity information for the 64,978 non-confidential substances on the TSCA Master Inventory File. The datafile contains no TSCA Confidential Business Information. New versions of the TSCA Inventory are issued at approximately six month intervals. The data provided for each chemical substance include the CAS Registry Number, Preferred CA Index Name, molecular formula, and other appropriate information, such as valid chemical names reported by submitters. The entries are in ascending CAS Registry Number order. The PMN Number to EPA Accession Number Link provides a cross-reference of these number for commenced PMNs on the confidential portion of the TSCA Master Inventory File. Neither this cross-reference nor the additional information included is TSCA Confidential Business Information. Provided on the diskette for each confidential commenced PMN are the PMN Case Number, EPA Accession Number, Generic Name, and EPA special flags. The sequence of the file is in ascending PMN case Number order with 'P' case numbers sorted first, followed by 'Y' case numbers.