Under the Toxic Substances Control Act (TSCA), EPA is finalizing an amendment to the significant new use rule (SNUR) for the chemical substance identified as 1-Propene, 2,3,3,3-tetrafluoro-, which was the subject of premanufacture notice (PMN) P-07-601. This action amends the SNUR to allow the manufacture and processing for certain uses without requiring a significant new use notice (SNUN). EPA is finalizing this amendment based on review of newly submitted exposure and toxicity data.