Environment

EPA Sets NOx Limits for U.S. Steel’s Keetac Taconite Facility in Minnesota

🇺🇸United States··Final Rule·Medium Impact·View source ↗

AI-generated summary for informational purposes only. Not legal advice. See the original source for the authoritative text.

🇬🇧 English

The rule sets nitrogen oxide emission limits for the indurating furnace at U.S. Steel’s Keetac taconite facility in Keewatin, Minnesota. The limits are designed to meet federal air-quality requirements for older industrial sources that must use the best available retrofit technology. Keetac will need to meet a 3.4 lbs/MMBtu NOx limit when using only natural gas, starting three years after the rule is issued. When using any other fuel mix, it must meet a 2.0 lbs/MMBtu limit starting five years after the rule is issued, unless EPA changes that limit. The facility may ask for a limited adjustment to the co-firing limit after collecting emissions data from installed control technology.

AI-generated summary. May contain errors. Refer to official sources for legal decisions.

Key Changes

  • Sets NOx emission limits for U.S. Steel’s Keetac taconite indurating furnace
  • Creates separate limits for natural gas-only firing and other fuel combinations
  • Allows Keetac to request a limited adjustment to the co-firing limit based on emissions monitoring data

Obligations

What this law requires

high

Operate the Keetac Grate Kiln indurating furnace so that NOx emissions do not exceed 3.4 lbs/MMBtu on a rolling 720-hour average when firing exclusively natural gas.

United States Steel's Keetac taconite facility
Beginning three years after promulgation of the final rule
operational
high

Operate the Keetac Grate Kiln indurating furnace so that NOx emissions do not exceed 2.0 lbs/MMBtu on a rolling 720-hour average when firing any fuel or combination of fuels other than exclusively natural gas, unless EPA promulgates a modified limit before that date.

United States Steel's Keetac taconite facility
Beginning five years after promulgation of the final rule
operational
medium

Determine compliance with the Keetac NOx BART emission limits using a rolling 720-hour average.

United States Steel's Keetac taconite facility
When the applicable NOx limit becomes enforceable
operational
medium

If Keetac seeks an adjustment to the cofiring NOx emission limit, the request must be submitted within 52 months from the final rule's effective date and must be based on CEMS data collected after installation of the NOx reduction technology; any adjusted limit may not exceed 2.5 lbs NOx/MMBtu as a 720-hour rolling average.

United States Steel's Keetac taconite facility
Within 52 months from the effective date of July 8, 2026
reporting

Affected Parties

U.S. Steel Keetac facilityTaconite production operators in Minnesota+2 more…

Tags

air quality,NOx emissions,taconite…