MINNESOTA SULFATE STANDARD
In the early 1970s, the Minnesota Pollution Control Agency (MPCA) adopted a sulfate water quality standard of 10 mg/L for waters used to produce wild rice. For decades it went unused. In the last 15 years, the MPCA has begun to enforce this standard and has drastically increased the number of lakes and rivers across the state where it will be applied.
On September 22, 2025, the MPCA concluded its public comment process for Keetac permits that include enforcing the 10 mg/L standard. By statute, MPCA was given until October 3, 2025, to issue a final decision on the variance application. To ensure sufficient time to carefully review all the additional information submitted by U. S. Steel and the 1,000+ comments submitted by the public, U. S. Steel granted the MPCA a four-month extension.
U.S. Steel granted the MPCA a second extension on February 4, 2026. During the one-month extension, the company will meet with the MPCA weekly to discuss technical issues and a schedule for issuing permit(s). If U. S. Steel and MPCA discussions bring any substantive changes, an additional public comment period may be required.
The future of Minnesota mines, local governments and other industries is critically affected by the potential enforcement of a 10 mg/L sulfate standard.
Scientists and impacted groups – who have worked for years to identify a workable solution – continue to advocate for a modern standard that is based on science, is proven to result in increased or stable wild rice, provides for site-specific standards, and is financially feasible to implement.
THE FACTS
Minnesota is the only state/province in North America with a sulfate standard.
Wild rice has been successful in waters with sulfate levels of 1,600 mg/L and beyond.
Many other factors, like iron and carbon content, greatly determine wild rice resilience.
Minnesota has 2,400 wild rice-producing lakes, and no two lakes are the same.
Our state’s sulfate standard cannot be one-size-fits-all.
According to the University of Minnesota, no single standard is correct.
HOW WE GOT HERE
The 10 mg/L sulfate standard was enacted in the 1970s based on research from the 1940s. Since then, years of scientific study and MPCA research show that this standard is not based on the best available science. A 2018 Governor’s Task Force on Wild Rice confirmed the need for a more holistic approach to understanding wild rice habitats.
Keetac wastewater permitting timeline: 1973-2026
1973: Minnesota Pollution Control Agency (MPCA) adopts sulfate water quality standard of 10 mg/L for waters used to produce wild rice.
2010–2011: Sulfate Standard first embedded in Keetac permits.
- June 17, 2010 — MPCA issues major permit modification adding the sulfate compliance schedule to Keetac’s NPDES/SDS permits.
- October 25, 2011 — MPCA Citizens’ Board approves reissuance of NPDES/SDS permits MN0031879 and MN0055948, including sulfate limits based on the wild rice sulfate standard.
- November 15, 2011 — MPCA publishes the formal Findings of Fact, Conclusions of Law, and Order approving the permits.
2011: A wild rice law is passed by the Minnesota Legislature that bound MPCA to a process to revise the numeric sulfate standard, establish criteria for determining and designating wild rice waters, and address seasonality.
2014: U. S. Steel (USS) submits a site-specific standard application requesting an alternate water quality standard for Hay Lake.
2015: Minnesota Legislature passes a law requiring MPCA to complete the 2011 rulemaking before including the 10 mg/L standard into discharge permits and requiring facilities to spend money on sulfate treatment.
2016: Legislation is passed specifically providing relief to Keetac’s sulfate permit limits. USS Keetac NPDES/SDS permits are the only permits in which the 10 mg/L standard has been applied.
April 24, 2018: MPCA announces it is withdrawing the wild rice rule from the rulemaking process. MPCA states they believe the science is accurate but need to determine how best to apply the science and affordably implement the rule.
June 29, 2021: Letter from MPCA to EPA Region V – states MPCA intends to begin working on Total Maximum Daily Load Studies (TMDLs). States that 873 NPDES dischargers are upstream of at least one of the 30 waters EPA proposed to list, with only 175 of those currently monitoring sulfate. Recognizes variances will be needed and that MPCA will need to work with EPA on industrial variances to ensure appropriate consideration of economic impacts, given that guidance on these dischargers is limited. The letter also recognizes there are varying background sulfate levels throughout the state.
February 2022: EPA sends letter to MPCA stating that the 2015 and 2016 legislation is in conflict with the Clean Water Act (CWA) and that the existing wild rice standard of 10 mg/L be enforced by the MPCA. EPA recommends MPCA work with the Legislature to eliminate the conflict.
August 2022: USS submits an updated 2014 Site Specific Standard (SSS) request.
December 2022: MPCA places the City of Keewatin NPDES permit on public comment. The discharge goes to Hay Lake. MPCA does not include requirements for the sulfate wild rice standard because the TMDL had not yet been completed.
September 2023: USS submits updated Keetac applications for industrial wastewater permits MN0031879 and MN0055948 to MPCA. These applications trigger the current review cycle.
May 2025: USS formally submits a variance request from the wild rice sulfate standard for both permits. On July 8, 2025, MPCA issues a preliminary decision to deny.
July 8, 2025: MPCA opens a 60‑day public comment period on the draft NPDES/SDS permits and the preliminary decision to deny the sulfate variance.
July 14, 2025: MPCA issues a news release announcing the draft permits, updated sulfate compliance schedules, and the preliminary denial of the variance.
September 3, 2025: MPCA hosts public meeting where 500+ people attend, 150+ people sign up to provide comments.
September 22, 2025: Comment period closes. More than 1,000 comments are received by the MPCA.
October 3, 2025: Statutory deadline for MPCA to issue final decision on USS’s variance application. USS grants MPCA four-month extension to review public comments and discuss technical issues and a schedule for issuing permits.
December 18, 2025: MPCA announces it will evaluate peer-reviewed science to validate the impacts of sulfate on wild rice and work to understand and document the variation in naturally occurring sulfate levels across the state.
February 4, 2026: USS grants MPCA a one-month extension to discuss technical issues and a schedule for issuing permits.
March 4, 2026: Date by which a permit plan will be finalized.
For many businesses and communities, a 10 mg/L sulfate standard is functionally unattainable. As a result, most organizations must request variances to the state’s antiquated standard. The MPCA has acknowledged that the sulfate standard is not a one-size-fits-all solution. Variances are a short-term solution, and ultimately the standard needs to be fixed as was required by law in 2011.
From smalltown wastewater facilities to mines employing thousands of Minnesotans, the cost of meeting the current 10 mg/L sulfate standard puts Minnesota at risk. Without a sulfate standard policy that follows modern science, addresses site-specific variables and contains cost, Minnesotans will not achieve the outcomes they deserve – thriving communities, good jobs, clean water AND healthy wild rice. Let’s not give up on real solutions.
LEADERS SPEAK ON MINNESOTA'S SULFATE STANDARD
Iron Ore Alliance, Iron Mining Association and Range Area Municipalities and Schools meeting August 19, 2025
Chrissy Bartovich, Senior director of environmental, U. S. Steel Corporation
Jake Friend, President, USW Local 2660
Adam Lantz, Mayor of Chisholm and small business owner
Pete Hyduke, Mayor of Hibbing
WHAT WE’RE DOING
Since 1960, U. S. Steel has invested hundreds of millions of dollars in environmental improvement measures. Here’s what we’re doing to protect our environment, our communities and a thriving Minnesota economy:
- Recently completed a crowd sourcing challenge through Wazoku to engage a global pool of experts on how to solve the sulfate situation at Keetac
- Installed state of the art scrubber technology
- Implemented dust collectors and low NOx burners
- Performing research into innovative sulfate technologies such as permeable reactive barriers
IT’S TIME FOR A REAL STANDARD
Thank you to everyone for advocating for sensible application of the sulfate water quality standard and wild rice protection. Your advocacy for iron mining and the Iron Range continues to make a real difference as the MPCA considers the Keetac variance application and permits, following the closure of the public comment period on September 22.
By statute, MPCA was given until Friday, October 3, 2025 to issue a final decision on the variance application. To ensure sufficient time to carefully review all the additional information submitted by U. S. Steel and the high volume of comments submitted by the public, U. S. Steel has granted the MPCA two extensions. This additional time will allow for a more complete review and provide opportunity for meaningful discussion on the application and draft permits.
Mining and the entire state of Minnesota will benefit from issuing permits that follow modern science, address site-specific variables, and contain cost. Minnesotans deserve thriving communities, good jobs, clean water, and healthy wild rice.