A federal watchdog agency is broadening its investigation into the handling of a key water pollution permit for PolyMet Mining's proposed Minnesota copper-nickel mine, giving the probe national scope.
Without issuing any findings on the PolyMet case, the Inspector General of the U.S. Environmental Protection Agency (EPA) has launched a nationwide audit of comparable water quality permits. Specifically, it will examine whether the permits adhere to federal law "based, in part," on the Inspector General's examination of PolyMet, which started in June. A memo announcing the move also cited additional hotline complaints that have been lodged since the one in January that launched the PolyMet inquiry.
The agency will fold its PolyMet findings into the national audit, which means it could be many months before anything is released.
The PolyMet permit is now the subject of three separate inquiries — one by the EPA, one by Minnesota's Legislative Auditor and one in Ramsey County court — after Minnesota environmentalists and a memo leaked to the Star Tribune revealed what have been called irregularities in its handling by federal and state regulators.
The expanded audit was announced in a Sept. 5 memo from Kathlene Butler, a director in the EPA Inspector General's Office, to David Ross, the EPA's assistant administrator for water.
"We initiated that work to determine whether the EPA followed appropriate Clean Water Act and NPDES regulations in Region 5 to review the PolyMet permit approved by Minnesota and issued in 2018," Butler wrote in the memo. "We will incorporate the results from our work assessing the PolyMet permit review into this nationwide audit of the EPA's NPDES permit reviews."
The National Pollution Discharge Elimination System (NPDES) regulates pollutants such as mercury and lead that can be discharged from point sources, such as industrial plants, into surface waters such as lakes and streams.
The Minnesota Pollution Control Agency issued an NPDES permit to PolyMet last year over serious reservations by the EPA's Region 5 Office in Chicago, which oversees Minnesota's enforcement of federal pollution laws.