The Center for Biological Diversity, Save Lake Superior Association, Save Our Sky Blue Waters, Friends of the Cloquet Valley State Forest, and Duluth for Clean Water sued the U.S. Fish & Wildlife Service, U.S. Forest Service, and U.S. Army Corps of Engineers, arguing that their approval of the PolyMet open-pit copper mine and land exchange in the Superior National Forest in northeastern Minnesota violates the Endangered Species Act (ESA). Plaintiffs argue that the 528-acre open-pit mine would destroy important habitat for the Canada lynx and northern long-eared bat, both classified as threatened under the ESA. Plaintiffs are seeking declaratory judgment that the federal agencies have violated the ESA and a court order enjoining the copper mine project pending completion of a new ESA analysis.