W. FLETCHER, Circuit Judge.
The Center for Biological Diversity, the Western Land Exchange Project, and the Sierra Club (collectively, "Appellants") bring suit against Asarco LLC ("Asarco"), a mining company, and the Department of Interior and the Bureau of Land Management (collectively, "BLM"). Appellants contend that the BLM's approval of a land exchange violates the National Environmental Policy Act ("NEPA"), 42 U.S.C. §§ 4321-70; the Federal Land Policy and Management Act ("FLPMA"), 43 U.S.C. §§ 1701-87; and the Mining Law of 1872, 30 U.S.C. §§ 21-54.
If the proposed exchange does not occur, the land will continue to be owned by the United States. In that event, Asarco will be permitted to conduct mining operations on the land only if it complies with the Mining Law of 1872. Specifically, Asarco will not be able to conduct a new mining operation on the land without first submitting a Mining Plan of Operations ("MPO") to the BLM. The MPO would have to include detailed information about the operations, management, monitoring, and environmental impacts of the proposed mining activities. The BLM would then have to approve the MPO before the new mining could proceed.
If the proposed exchange occurs, Asarco would take fee simple ownership of the exchanged land. In that event, Asarco's use of the land would not be subject to the requirements of the Mining Law of 1872. Asarco has spent sixteen years, and considerable amounts of time and money, seeking to achieve private ownership of the exchanged land, which would allow Asarco to avoid having to prepare the MPOs that are required so long as the land remains in public hands.
As part of the process of approving the land exchange, the BLM prepared a Final Environmental Impact Statement ("FEIS") pursuant to NEPA. In the FEIS, the BLM assumed without analysis that the MPO process would impose no constraints on, and would have no effect on, the manner in which Asarco would conduct new mining operations on the exchanged land. That is, the BLM assumed that the manner and extent of Asarco's new mining operations would be the same whether or not the United States owned the land. Because of this assumption, the BLM did not compare the environmental effects of exchanging the land with the effects of not exchanging the land.
Under these circumstances, we hold that the BLM has not "taken a `hard look' at the environmental consequences of its proposed action" in violation of NEPA, and that its action was therefore arbitrary and capricious. Blue Mountain Biodiversity Project v. Blackwood, 161 F.3d 1208, 1211 (9th Cir. 1998). We also hold that the BLM's approval of the proposed land exchange was a violation of FLPMA and similarly arbitrary and capricious. Webb v. Lujan, 960 F.2d 89, 91 (9th Cir. 1992). We therefore reverse the decision of the district court approving the actions of the BLM.