The U.S. Forest Service is responsible for managing the Cabinet Mountain Wilderness Area in northwestern Montana. The wilderness area consists of approximately 94,272 acres and is part of the Cabinet-Yank ecosystem, one of only six ecosystems in the continental United States that supports populations of grizzly bears. The bears are listed as an endangered species under the Endangered Species Act. ASARCO, which holds 149 unpatented mining claims (covering 2,980 acres) located in the wilderness area, has applied to the Forest Service for permission to conduct exploratory drilling to assess the extent of copper and silver deposits in the area. ASARCO proposes to drill 36 drill holes on 22 sites in a portion of the wilderness area with a similar level of activity in each of the next three years. Each drill site is limited to an area of 20 feet by 20 feet. Over the four-year period, these sites will occupy a combined area of about 0.5 acre. 

During the time drilling is being conducted, the drilling equipment, personnel, and supplies would be brought in by helicopter, and the company has proposed that the workers would camp overnight at the site while the drilling was being conducted. It is estimated that only about a dozen grizzly bears may inhabit the portion of the wilderness area where the drilling will take place. If the exploratory drilling reveals significant deposits of copper or silver at any particular site, the company might seek a permit to conduct developmental exploration or mineral extraction at the site. This would have some potential to impact the feeding and denning activities of the bears—and, in turn, their reproductive success—depending on where the activity is conducted, when it is conducted, and how substantial the activity is. Should issuance of the requested exploratory drilling permit to ASARCO be considered “a major federal action significantly affecting the environment,” thus requiring the Forest Service to prepare an environmental impact statement (EIS) pursuant to the National Environmental Policy Act (NEPA)?