MINNEAPOLIS — Environmental Protection Agency documents show that its staffers were critical of how Minnesota regulators drafted a key permit for the planned PolyMet copper-nickel mine. And they show the officials concluded the permit would violate federal law because it lacked specific water pollution limits.

The EPA released the documents after a court challenge by WaterLegacy and other groups.

WaterLegacy attorney Paula Maccabee says that while the EPA had serious concerns, they weren’t reflected in PolyMet’s final permit, which did not set limits for specific pollutants.

EPA staffers read one document over the phone to staff at the Minnesota Pollution Control Agency last year but never filed formal written comments expressing concerns.

The Minnesota agency said it was preparing a statement. EPA officials did not immediately respond to a request for comment.

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