Air Plan Approval; Minnesota; Revision to Taconite Federal Implementation Plan
Key claim: The EPA is finalizing NOx BART emission limits for U.S. Steel’s Keetac taconite facility indurating furnace in Minnesota, setting limits of 3.4 lbs NOx/MMBtu for natural gas firing and 2.0 lbs NOx/MMBtu for other fuels under a rolling 720-hour average compliance schedule.
Abstract
(Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA) is revising the Original 2013 Federal Implementation Plan (FIP) by finalizing nitrogen oxide (NOX) 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 NOX 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 NOX 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 NOX/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 NOX/MMBtu as a 720-hour rolling average, based on collection of continuous emission monitoring system (CEMS) data after installation of the NOX reduction technology.
Why this matters
NOx BART (Best Available Retrofit Technology) determinations under the Regional Haze program directly translate into capital and operating costs for specific industrial facilities, and taconite indurating furnaces are among the largest NOx sources in the Upper Midwest. Finalizing facility-specific limits at Keetac closes out a long-running FIP dispute and sets a precedent for how EPA calibrates BART limits (natural gas vs. other fuels, averaging window) at other Minnesota taconite plants.