BILLINGS, Mont. (AP) â¿¿ Environmentalists have filed a lawsuit seeking to derail efforts by the federal government to lease an estimated 2 billion tons of coal near two major Wyoming mines. The lawsuit filed Wednesday in U.S. District Court in Washington, D.C., targets four recent and proposed coal lease sales in the Powder River Basin. That's an area of Montana and Wyoming that produces more coal than any other region of the country. The Sierra Club and Wild Earth Guardians say mining and burning coal from the federal leases would release huge amounts of the greenhouse gas carbon dioxide, exacerbating climate change. The Bureau of Land Management leases are near two of the world's largest coal mines: Arch Coal's Black Thunder mine and Peabody Energy's North Antelope Rochelle mine. The BLM addressed climate change issues in its decision to sell the leases but said it wasn't its place to regulate emissions from burning the fuel.