The Environmental Protection Agency (EPA) is taking final action to revise certain portions of the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Radon Emissions from Operating Mill Tailings. The revisions for this final action are based on the EPA's determination as to what constitutes generally available control technology or management practices (GACT) for this area source category. We are also adding new definitions to the NESHAP, revising existing definitions and clarifying that the NESHAP also applies to uranium recovery facilities that extract uranium through the in-situ leach method and the heap leach method.