In re Reissuance of NPDES/SDS Permit to United States Steel Corp.Annotate this Case
The Supreme Court held that groundwater is a Class 1 water under Minnesota law and therefore subject to secondary drinking water standards promulgated by the United States Environmental Protection Agency (EPA).
In 2018, the Minnesota Pollution Control Agency (MPCA) issued a National Pollutant Discharge Elimination System/State Disposal System permit to United States Steel Corporation (U.S. Steel) governing U.S. Steel's Minntac Tailings Basin Area in Mountain Iron and setting a groundwater sulfate limit of 250 mg/L at the facility's boundary that U.S. Steel must meet by 2025. On appeal, U.S. Steel argued that the MPCA did not have the authority to impose the sulfate standard in the permit because the EPA's secondary drinking water standards apply only to bodies of water classified as Class 1 waters and that groundwater is not classified as Class 1. The court of appeals agreed and reversed the MPCA's decision. The Supreme Court reversed, holding (1) groundwater is a Class 1 water under Minnesota law; and (2) therefore, the MPCA correctly exercised its authority by applying the Class 1 secondary drinking water standards to the permit.