Under the Toxic Substances Control Act (TSCA), EPA is amending a significant new use rule (SNUR) for perfluoroalkyl sulfonate (PFAS) chemical substances to add PFAS chemical substances that have completed the TSCA new chemical review process, but have not yet commenced production or import and is designating (for all listed PFAS chemical substances) processing as a significant new use. EPA is also finalizing a SNUR for long-chain perfluoroalkyl carboxylate (LCPFAC) chemical substances that designates manufacturing (including importing) and processing for use as part of carpets or for treating carpet (e.g., for use in the carpet aftercare market) as a significant new use, except for use of two chemical substances as a surfactant in carpet cleaning products. For this SNUR, EPA is also making an exemption inapplicable to persons who import or process the LCPAC chemical substances as part of an article. Persons subject to these SNURs will be required to notify EPA at least 90 days before commencing any significant new use. The required notifications will provide EPA with the opportunity to evaluate the intended use and, if necessary, to prohibit or limit that activity before it occurs.