PolyMet Environmental Review

What is environmental review?

When a major project, like the PolyMet sulfide mine, has the potential to create significant environmental harm, the agencies taking action and issuing permits for the project are required by law to study the environmental, cultural, and economic effects of the project. The document collecting this information is called an “environmental impact statement” or “EIS.” Environmental review laws were adopted so that an EIS would help government agencies choose the least environmentally harmful alternatives and have a scientific basis on which to grant or deny permits.

In the case of the PolyMet mine, as with many other projects where there is strong economic or political pressure, the environmental review process was seriously flawed. WaterLegacy and our experts documented shortcomings of the PolyMet EIS process in written comments from 2009 through 2015, including:

  • Unproven assumptions by PolyMet were used to deny or minimize harm.
  • Less dangerous alternatives were not seriously considered.
  • Health impacts were not adequately assessed.
  • Tribal science and concerns were not addressed.
  • The feasibility of the PolyMet project was based on a “bait-and-switch” plan for expansion that was only disclosed after the Final EIS was already approved by the State of Minnesota.

What’s the current status?

When the PolyMet Draft EIS was first reviewed by the U.S. Environmental Protection Agency (“EPA”) in 2010, the PolyMet Draft EIS was rated “inadequate” and the sulfide mine project was rated “environmentally unacceptable.” However, by March 22, 2019, the Minnesota Department of Natural Resources (“DNR”), the U.S. Forest Service and the U.S. Army Corps of Engineers (“Army Corps”) had all approved the PolyMet Final EIS and had taken action based on its assumptions.

WaterLegacy and our allies asked the DNR to require a Supplemental EIS when we learned in 2018 that the economic feasibility of the PolyMet mine project was based on a plan for massive expansion of the mine. But, this request was denied both by the DNR and by the Court of Appeals on review. In state courts, WaterLegacy and our allies are challenging the permits issued to PolyMet, no longer the process of environmental review. Lawsuits in federal court can still challenge the PolyMet Final EIS as well as agency approvals for the project.

What’s the history of environmental review?

WaterLegacy has advocated and organized to oppose the PolyMet mine and call attention to flaws and improper assumptions in PolyMet EIS documents since 2009. Here is a brief chronology of the PolyMet environmental review process:


Environmental review begins. The Scoping Report prepared by the Minnesota DNR and the U.S. Army Corps in October 2005 identified alternative “brownfield” locations for PolyMet tailings waste disposal. WaterLegacy has repeatedly asked that alternatives for a lined, filtered or “dry stack” (water removed) tailing storage facility on a stable foundation on one of these “brownfield” sites be considered. None of these alternatives were analyzed.
Excerpt of map in DNR PolyMet NorthMet Scoping Report (2005)


The  PolyMet Draft EIS was released by the Minnesota DNR and U.S. Army Corps in October 2009.


WaterLegacy filed comments on February 3, 2010, detailing the many deficiencies of the PolyMet Draft EIS and concluding, “the PolyMet NorthMet draft environmental impact statement is inadequate and insufficient. It appears to have been written to justify and promote the PolyMet NorthMet project, rather than to assess its environmental impacts


The U.S. EPA submitted comments on February 18, 2010, rating the EIS study as “Inadequate” and concluding that the PolyMet mine project was “Environmentally Unsatisfactory (EU)” because EPA “has identified adverse environmental impacts that are of sufficient magnitude that EPA believes the proposed action must not proceed as proposed.” EPA explained:

EPA has assigned the EU rating because our review of the [draft EIS] DEIS determined that the proposed action will result in environmentally unsatisfactory water quality impacts. Specifically, EPA believes that the project will exceed water quality standards because of discharges during the life of the mining operation and on a long-term basis, including the post-closure period. These water quality impacts are largely related to water that contacts acid-generating waste rock and mine faces and to wastewater escaping the tailings basin through seeps and in groundwater. EPA also finds the wetlands mitigation plan environmentally unacceptable because it does not provide mitigation for all impacts to wetlands, particularly for indirect impacts.

From WaterLegacy’s perspective, EPA’s 2010 concerns about the PolyMet mine have never been adequately resolved.


The PolyMet Supplemental Draft EIS (“SDEIS”) was released to the public in November 2013. Documents from agency files suggest that the Co-Lead Agencies DNR and the Army Corps of Engineers actually developed the mine plan described in the PolyMet SDEIS. (See e.g. the 2015 Forest Service Draft Land Exchange Record of Decision on page 4).


WaterLegacy filed extensive comments, expert opinions, and 54 exhibits challenging the PolyMet SDEIS on March 13, 2014. In addition, as a result of organizing, more than 58,000 public comments were submitted in response to the PolyMet SDEIS; nearly all of them opposed the PolyMet sulfide mine.

WaterLegacy’s comments emphasized:

[T]he SDEIS is inadequate and the project is likely to pose significant adverse impacts to the environment, to human health, to environmental justice, and to tribal rights and resources. The SDEIS is data poor, and its modeled outcomes are determined by unsubstantiated and unreasonable assumptions, rather than by empirical information and field experience.

The PolyMet proposed action described in the SDEIS also fails to satisfy Clean Water Act Section 404 requirements. The SDEIS does not demonstrate that the project is the least environmentally damaging practicable alternative or that its impacts on aquatic resources of national importance will be mitigated. The proposed Land Exchange serves a narrow private interest, rather than the public interest, and contradicts both federal policy and federal fiduciary responsibilities to protect tribal resources. .

WaterLegacy’s experts detailed flaws in the PolyMet SDEIS:
Wetlands and mercury expert, Brian Branfireun, explained that PolyMet sulfate and mercury discharge and hydrologic changes to wetlands could result in mercury bioaccumulation and downstream harm.

Read Brian Branfireun’s SDEIS Expert Opinion

Geologist J.D. Lehr explained that the underlying geology of the mine and tailings site were assumed rather than studied, with dangerous consequences for both water quality and dam stability.

Read J.D. Lehr Expert Opinion and Figures

Engineer and hydrologist, Donald Lee, explained that the SDEIS did not comply with the law in analyzing impacts or alternatives and that the assumptions about capture of polluted seepage were not reasonable.

Read Don Lee’s SDEIS Expert Opinion

Retired DNR chemist, Bruce Johnson, explained that assumptions regarding chemistry of wastes, leachates and water quality were not scientifically defensible.

Read Bruce Johnson’s SDEIS Expert Opinion


The Co-Lead Agencies – U.S. Forest Service as well as the U.S. Army Corps, and Minnesota DNR – released the PolyMet Final EIS on November 6, 2015.


On December 14, 2015, WaterLegacy submitted to the Co-Lead Agencies more than 200 pages of technical comments, six expert reports, and 36 new exhibits opposing the PolyMet Final EIS (also “FEIS”) and requesting the Final EIS be rejected as inadequate. An additional 30,000 public comments were submitted in the short public comment period.

WaterLegacy’s comments included the following conclusions:

[T]he environmental review provided for Minnesota’s first proposed copper-nickel sulfide mine fails each of [the] tests for the quality, integrity, and content of an EIS.

Even where the FEIS has appeared to respond to comments, that response has been inadequate, if not affirmatively misleading.

The FEIS is highly reliant on the project proponent’s modeling and on unsubstantiated assumptions from the project proponent for its conclusions.

The FEIS not only fails to discuss opposing scientific views, it misrepresents peer-reviewed literature, the nature of tests conducted regarding the project, and even the documents contained in its own record.

The Project alternatives analysis, intended by law to be the “heart” of the EIS, is a scant few pages of the FEIS, and inadequate documentation is provided to support the rejection of substantive alternatives.

The FEIS fails to analyze issues of great significance and concern, including the synergistic effects of the project on mercury methylation, contamination of fish, and resulting impacts to human health and environmental justice and the indirect and cumulative, as well as direct impacts, of the Project on wetlands and wetlands functions.

WaterLegacy experts explained concerns about PolyMet’s Final EIS and Mine Plan:

Wetlands and mercury expert, Brian Branfireun, concluded: “It is my opinion that the NorthMet development could create a substantial risk of ecologically significant increases in water column and fish methylmercury concentrations in downstream waters, including the St. Louis River.”

Read Brian Branfireun’s Final EIS Expert Opinion.

Wetlands expert, Morgan Robertson, concluded that PolyMet’s plan [since changed] to replace wetlands outside the St. Louis River watershed and the Lake Superior Basin would violate federal law and that “as a result of failure to determine secondary impacts on wetlands from the proposed PolyMet project, the FEIS is inadequate.”

Read Morgan Robertson’s Final EIS Expert Opinion

Hydrologist and engineer, Donald Lee, criticized claims made in the Final EIS for efficacy of capture of polluted seepage from the tailings waste facility and waste rock pile, stating that the Final EIS conclusions were “based on assumptions or performance that are not justified or supported by data” and that the proposed seepage collection “is unlikely to work as anticipated.”

Read Donald Lee’s Final EIS Expert Opinions on Tailings Seepage Collection and Waste Rock Seepage Collection

Field chemist and retired DNR regulator, Bruce Johnson, concluded that the PolyMet Final EIS used faulty assumptions and grossly underestimated the concentrations of toxic pollutants and the impacts of tailings seepage on water quality.

Read Bruce Johnson Final EIS Expert Opinion

Duluth child psychiatrist, Margaret Saracino, detailed concerns about methylmercury increases from the PolyMet mine and the effects “on human health of those living in the area,” noting that “[f]etuses, infant, and young children are four to five times more sensitive to the adverse effects of methylmercury exposure than adults.”

Read Margaret Saracino’s Final EIS Expert Opinion

Duluth family physician, John Ipsen, concluded that the PolyMet Final EIS was inadequate to address the risks of particulate air pollution to the mineworkers and to people living in surrounding communities, and he opined that a “Health Impact Assessment from a qualified independent evaluator” was necessary.

Read John Ipsen’s Final EIS Expert Opinion


Despite all of the advocacy, public comments and expert opinions, the Minnesota DNR Record of Decision on March 3, 2016 found that the PolyMet Final EIS was “adequate.”


PolyMet posted a new Technical Feasibility Report on the official Canadian stock exchange site and provided new information to the press and investors in late March 2018. PolyMet’s new information showed that mine costs had increased and projected profit was down. To increase the rate of return to investors, PolyMet described expansions up to three times the size of the mine in the Final EIS.


WaterLegacy and our allies petitioned for a Supplement to the Final EIS on July 18, 2018, based on PolyMet’s new “bait-and-switch” expansion plans and other new proposed project changes. The DNR denied the request for additional environmental review.

The U.S. Forest Service January 9, 2017 Record of Decision approving the PolyMet Land Exchange and the U.S. Army Corps March 21, 2019 Record of Decision Granting a Section 404 (Wetlands Destruction) Permit to PolyMet  implicitly approved the Final EIS in making these decisions.