The U.S. Environmental Protection Agency (EPA) alerted the state of Wisconsin and the Fond du Lac Band of Lake Superior Chippewa that the water discharges from the propose PolyMet copper-nickel mine project discharges "may affect . . . the quality of the waters" of their own jurisdictions.

Minnesota Public Radio reported that the EPA is required, under the Clean Water Act, to alert a state if it determines a project in another state might have the potential to affect its water quality. The mine would be located near Babbitt and Hoyt Lakes on the eastern side of the Iron Range in northern Minnesota.

The Fond du Lac Band and the state of Wisconsin now have the ability to request a hearing on the matter.

PolyMet CEO Jon Cherry said in a statement that the company disagrees with the federal regulators’ assessment. Cherry said the environmental review of the PolyMet project —conducted before state regulators approved the mine in 2018 — found that the mine’s planned water treatment would improve water quality in the St. Louis River, which snakes from the forests of northeastern Minnesota to empty into Lake Superior at the twin ports of Duluth and Superior.

“I am hard-pressed to understand how our treated water can meet water quality standards at the point of discharge and at other downstream communities closer to the project site, and actually reduce overall mercury loading to the river, but somehow 'may affect' water in places located more than 100 river miles downstream,” Cherry said.

But the Fond du Lac Band celebrated the EPA’s determination. Earlier this year, a federal district court judge ruled that the EPA had violated the law by not determining whether the PolyMet project “may affect” the water quality of the Fond du Lac Band’s reservation downstream, pursuant to the federal Clean Water Act.

This decision from the EPA now gives the Band the opportunity to object to the U.S. Army Corps of Engineers’ issuance of a required permit that PolyMet needs to operate, known as a Section 404 permit, which regulates the impacts of water discharge on nearby wetlands. The Corps of Engineers had put that permit on hold while the EPA conducted its review.

According to the EPA, the Band and Wisconsin now have 60 days to formally object to the permit in question, and to request a public hearing. The Corps of Engineers would then review recommendations and any additional information presented at the hearing to decide whether to issue, modify or deny the permit.

PolyMet’s NorthMet mine project would be the first copper-nickel mine in Minnesota. After a contentious permitting and review period that stretched well over a decade, the mine received state and federal clearance in 2018.

But since then, the project has been mired in litigation, and several key permits have been put on hold.

In April, the Minnesota Supreme Court sent the project’s Permit to Mine — the primary permit PolyMet needs in order to operate — back to the Minnesota Department of Natural Resources for an additional fact-finding hearing before an administrative law judge.