The Environmental Protection Agency (EPA) is revising a Federal implementation plan (FIP) addressing the requirement for best available retrofit technology (BART) for the United States Steel Corporation's (U.S. Steel) taconite plant located in Mt. Iron, Minnesota (Minntac or Minntac facility). We are revising the nitrogen oxides (NO<INF>X</INF>) limits for U.S. Steel's taconite furnaces at its Minntac facility because new information has come to light that was not available when we originally promulgated the FIP on February 6, 2013. The EPA is finalizing this action pursuant to sections 110 and 169A of the Clean Air Act (CAA or the Act).