EPA is finalizing a significant new use rule (SNUR) under the Toxic Substances Control Act (TSCA) for the chemical substance Pentane, 1,1,1,2,3,3-hexafluoro-4-(1,1,2,3,3,3-hexafluoropropoxy)- that was the subject of premanufacture notice (PMN) P-07-204. This action requires persons who intend to manufacture (including import) this chemical substance for an activity that is designated as a significant new use by this final rule to notify EPA at least 90 days before commencing that activity. The required notification will provide EPA with the opportunity to evaluate the intended use and, if necessary, to prohibit or limit that activity before it occurs.