EPA is developing a significant new use rule (SNUR) under section 5(a)(2) of the Toxic Substances Control Act (TSCA) for certain uses of Inactive Inventory Per- and Polyfluoro Alkyl Substances (PFAS). Persons subject to the Inactive Inventory PFAS SNUR would be required to notify the EPA at least 90 days before commencing manufacture or processing for any use that EPA has determined is a significant new use. The required notifications would initiate EPA's evaluation of the intended use within the applicable review period. Manufacture and processing for the significant new use would be unable to commence until EPA has conducted a review of the notice, made an appropriate determination on the notice, and taken such actions as are required in association with that determination.