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

Document 2026-11432 is a Final Rule published by the Environmental Protection Agency in the Federal Register on June 8, 2026, with an effective date of July 8, 2026. The U.S. Environmental Protection Agency (EPA) is revising the Original 2013 Federal Implementation Plan (FIP) by finalizing nitrogen oxide (NO<INF>X</INF>) emission limits for the indurating furnace at United States Steel's (U.S. Steel) Keetac taconite facility (Keetac) in Keewatin, Minnesota to satisfy the requirement for best available retrofit technology (BART) at taconite facilities. The EPA is finalizing the following NO<INF>X</INF> BART emission limits for the Keetac Grate Kiln indurating furnace, with compliance to be determined on a rolling 720-hour average: 3.4 pounds (lbs) of NO<INF>X</INF> per million British Thermal Unit (MMBtu) when firing exclusively natural gas, which will become enforceable beginning three years after promulgation of a final rule; and 2.0 lbs NO<INF>X</INF>/MMBtu when firing any fuel or combination of fuels other than exclusively natural gas, which will become enforceable five years after promulgation of a final rule, unless before that date the EPA promulgates a modified limit. The final rule allows Keetac, within a period of 52 months from the effective date of the final rule, the option to seek a potential adjustment of the cofiring emission limit, not to exceed 2.5 lbs NO<INF>X</INF>/MMBtu as a 720-hour rolling average, based on collection of continuous emission monitoring system (CEMS) data after installation of the NO<INF>X</INF> reduction technology. View the original at https://www.federalregister.gov/documents/2026/06/08/2026-11432/air-plan-approval-minnesota-revision-to-taconite-federal-implementation-plan.

No. Document 2026-11432 is not classified as economically significant under Executive Order 12866. Economically significant rules require OIRA review and are estimated to have impacts of $100 million or more per year.