U.S. Steel Corp. operates a taconite mine and processing plant known as Keetac north of Keewatin, where it produces taconite pellets for use at iron and steel mills.
Keetac operates under an existing air permit and two industrial wastewater permits: one for the discharges from the mining area and one for the tailings basin. U.S. Steel has applied to combine its two wastewater permits into one permit that covers both the mine and tailings basin.
Our role
The Minnesota Pollution Control Agency remains committed to protecting human health and the environment and supporting sustainable job growth in the state.
The MPCA is responsible for issuing and enforcing permits that limit emissions and discharges from Keetac’s operations to protect the environment and health of Minnesotans. Those permits reflect current state law and regulations.
The MPCA issued the facility’s air permit on Jan. 16, 2025, and U.S. Steel submitted an application for a major permit amendment in December 2025.
The MPCA made draft industrial wastewater permits for the facility available for public comment in the summer and fall of 2025.
The MPCA received more than 1,000 comments during the public comment period for the Keetac wastewater discharge permits. In consideration of comments related to affordability, the MPCA requested additional information from U.S. Steel for its permits at Keetac. We continue to work with U.S. Steel to address compliance with the proposed sulfate effluent limits and on other issues raised in the public comments.
On March 4, 2026, U.S. Steel submitted an application for an industrial wastewater discharge permit that would combine its two wastewater permits into one. The agency is reviewing the application. After the MPCA completes its review and develops a single wastewater permit, we will place the permit on public notice. This will likely take place later in 2026.
We are committed to continuing to provide updates throughout this process.
U.S. Steel applied for an updated air permit authorizing the replacement of four wet scrubbers with dry cartridge filters (fabric filters). Visit the posting in SmartComment to review the draft document and provide feedback. The comment period runs March 17-April 16, 2026.
Project information
U.S. Steel has operated the Keetac facility since 1967 and produces about 6 million tons of taconite pellets per year. The facility consists of the Keetac plant area and a nearby tailings basin.
Air quality permit
U.S. Steel applied for an updated air permit authorizing the replacement of four wet scrubbers with dry cartridge filters (fabric filters). The existing scrubbers and new fabric filters control ore handling equipment.
The MPCA has drafted an air permit for Keetac and will conduct a 30-day public comment period. The draft permit for this amendment will require U.S. Steel to:
- vent emission units to current control equipment until startup of new fabric filters
- submit construction and startup notifications for each new fabric filter
- conduct performance testing within 180 days of startup for filterable particulate matter and particulate matter and every 60 months thereafter
The public comment period for the air permit is open March 17-April 16, 2026.
