Federal Approval: PolyMet Wetlands Destruction Permit 

What is the wetlands destruction permit?

Under the Clean Water Act, destruction of wetlands that are waters of the United States is prohibited unless the U.S. Army Corps of Engineers (Army Corps) grants a Section 404 permit to destroy (“dredge and fill”) wetlands. The proposed PolyMet mine would destroy and degrade wetlands, so a Section 404 permit is required for its proposed sulfide mine.

Under Section 401 of the Clean Water Act, any state where a project is located has the right to object to an Army Corps permit that could result in violation of state water quality standards. The state’s approval of a federal wetlands destruction permit, with or without conditions, is called a Section 401 certification. Section 401 of the Clean Water Act also describes rights of downstream states – including tribes with “treatment as a state” to object to federal permits that would violate a downstream state’s water quality standards. WaterLegacy has advocated for federal recognition of the authority of downstream tribes (the Fond du Lac Band of Lake Superior Chippewa in the case of the PolyMet mine project) to object to federal permits.

Proposed PolyMet site wetland floor (2017). Photo by Robin Heil.

What’s the current status?

The U.S. Army Corps granted a Section 404 wetlands destruction permit to PolyMet on March 21, 2019. This federal permit allows PolyMet to directly destroy 933 acres of wetlands and requires that PolyMet buy another 162 acres of “credits” for wetlands destruction. The Army Corps decided that no alternatives to the mine or waste storage were required, and decided no additional environmental review was needed either due to likely project expansion or changes in PolyMet’s proposal.

The Minnesota Pollution Control Agency (MPCA) issued a (Section 401) certificate that added some monitoring, but concluded that PolyMet wetlands destruction would not violate state water quality standards, based on PolyMet’s assumptions about polluted seepage and mercury contamination.

Although the Fond du Lac Band of Lake Superior Chippewa (the Band) has a stringent water quality standard for mercury that is likely to be violated by PolyMet pollution and wetlands destruction, the Band had no chance to exercise its rights to object to the PolyMet wetlands destruction permit. Despite explicit written requests from the Band, the U.S. Environmental Protection Agency (EPA) failed to provide the notice required under the Clean Water Act that would trigger the Band’s authority as a downstream state, to object to the Army Corps’ PolyMet permit.

What has been done to oppose the permit?

WaterLegacy Comments

WaterLegacy submitted separate detailed comments and expert reports to oppose the PolyMet Section 404 permit as a violation of the Clean Water Act.

WaterLegacy argued against state certification of the PolyMet wetlands destruction permit.

Wetlands Replacement

Both federal and state law allow wetlands destruction if the project proponent “replaces” the wetlands, which has come to mean restoring or preserving wetlands someplace else. WaterLegacy’s wetlands expert Morgan Robertson, Ph.D. showed that the proposed wetland replacement plan in the PolyMet final environmental impact statement (EIS) was outside both the St. Louis River watershed and the Lake Superior Basin and violated federal law.

Wetlands on proposed PolyMet mine site. Photo from the Department of Natural Resources.

As a result, PolyMet’s wetlands replacement plan was changed to provide replacement wetlands in the Lake Superior Basin and, potentially, in the St. Louis River watershed. This is a positive change. However, the Army Corps failed to allow public comments or study of PolyMet’s new “wetlands replacement” plan. This new plan lacks basic requirements to make sure benefits to wetland ecosystems in the new PolyMet wetland replacement plan are real.

Secondary Wetlands Destruction

In the PolyMet Final EIS, the agencies never settled on what the secondary harm to wetlands would be. The Final EIS said total wetland acres destroyed or degraded could range as high as either 7,694 acres or 6,569 acres, and then stated that most of this damage was not “likely.” Yet, Army Corps allowed PolyMet to provide only 162 acres of replacement “credits” to cover damage or destruction due to secondary effects of the proposed PolyMet mine.

In July 2017, WaterLegacy submitted to the Army Corps an expert opinion by Jonathan Price, PhD, on the impacts of the proposed PolyMet mine on wetlands. Dr. Price concluded,

USACE [Army Corps] potentially severely under-predicts the potential damage to wetland function and consequently, would require insufficient compensation for indirect wetlands impacts.

Wetlands Destruction and Mercury Contamination

In response to Brian Branfireun’s expert report on the Final EIS and comments from WaterLegacy and the Fond du Lac Band, PolyMet provided MPCA with a new “analysis” denying that its proposed mine would increase mercury contamination of fish. Dr. Branfireun submitted an expert opinion harshly criticizing both PolyMet’s analysis and MPCA’s reliance on it to certify the proposed PolyMet wetlands destruction permit.

In my opinion, PolyMet’s Cross-Media Analysis is a straw man . . . the weight of the scientific evidence indicates that the NorthMet project [ ] would create a substantial risk of ecologically significant increases in water column and fish methylmercury concentrations in downstream waters, including the St. Louis River due to changes in wetland biogeochemical processes (primarily mercury methylation) driven by hydrological impacts of pit dewatering, subsequent changes to wetland biogeochemistry as a function of these changes, and aqueous sulfate discharges to headwaters

Read Brian Branfireun, Expert Opinion on Section 401 Certification for PolyMet Project (Jan. 20, 2019). 


WaterLegacy has not filed suit in federal court challenging the PolyMet wetlands destruction permit and the Final EIS. Federal lawsuits have been filed in the District of Minnesota federal court by EarthJustice, representing several conservation groups, and by the Fond du Lac Band of Lake Superior Chippewa.