In a novel attempt to enforce a longstanding Minnesota rule protecting wild rice, the Environmental Protection Agency is investigating U.S. Steel’s taconite mine, Keetac, for repeatedly releasing a rice-killing pollutant into surface waters.
The mine and tailings site in Keewatin broke sulfate limits set in two wastewater permits 299 times between 2019 and 2022, the EPA alleged in a May notice that only recently was publicly revealed. The agency could eventually impose fines, but the notice of violation it sent to U.S. Steel is not a final decision.
Sulfate, a mineral salt, does not occur naturally in high levels in water in northeast Minnesota. It comes from multiple sources, such as sewage plants, some power stations and mines that process rock containing sulfide. In the mucky bottoms of lakes, it’s been shown to smother the roots of growing wild rice plants, gradually snuffing out the plant that re-grows annually from fallen seeds.
U.S. Steel said in a statement that although it has tested several technologies, there is no workable way to stop the sulfate releases. Simultaneously, the company argues it’s not violating any water-pollution rules because of changes in state law.
The EPA is accusing the company of breaking a standard that limits sulfate to 10 parts per million (ppm) in streams, rivers and lakes where rice has historically grown. The rule has been on the books in Minnesota for more than half a century, but not enforced until recently. In 2011, 2015 and 2016, lawmakers limited the rule or directed regulators to rewrite it.
“The permit states that the sulfate effluent limits in the interim are for monitoring purposes and are effective limits when U.S. Steel is notified by MPCA that limits are considered final. That has not occurred,” Andrew Fulton, a spokesman for U.S. Steel, wrote in an email.
The Minnesota Pollution Control Agency noted in a 2017 inspection report that it could not enforce the standard on the company, according to documents obtained in a Freedom of Information Act request by the environmental group CURE.
But the state has started to enforce the sulfate rule in recent years because the EPA directed it to do so in 2022. That same year, the federal agency started looking closely at Keetac. Federal inspectors visited the mine in October 2022, the first time the EPA noted that the site was releasing more sulfate than the limits in its permits.