Air Plan Approval; Minnesota; Revision to Taconite Federal Implementation Plan

The Environmental Protection Agency (EPA) is proposing to modify nitrogen oxide (NO<INF>X</INF>) emission limits for the indurating furnace at United States Steel's (U.S. Steel's) Keetac taconite facility in Keewatin, Minnesota (Keetac), to satisfy the requirement for best available retrofit technology (BART) at taconite facilities. EPA is proposing this action pursuant to sections 110 and 169A of the Clean Air Act (CAA).