Environmentalists launched a legal fight Thursday challenging federal government leasing to oil and gas companies of nearly 400,000 acres of public land in Wyoming, Utah and Colorado.

Their lawsuit filed in federal court contends Bureau of Land Management officials failed to disclose the foreseeable environmental impact and billions of dollars in societal costs of oil and gas extracted from public lands. It demands that the BLM conduct full environmental impact analyses, as required under the National Environmental Policy Act, before leasing rights to drill.

“This is one of the greatest environmental and social justice challenges we face,” WildEarth Guardians attorney Tim Ream said after he and colleagues based in western states filed the lawsuit in U.S. District Court in Washington, D.C. “In a nutshell, the government has been hiding the climate change impacts of its oil and gas leasing program using public land.

“What is the cost to society? … The government is legally required to disclose impacts of oil and gas lease sales of public land on the environment. Climate change and emissions impacts have to be disclosed,” Ream said.

“The question is whether or not impacts are reasonably foreseeable. That is the legal standard under NEPA. It does not matter whether the oil and gas is burned in the United States of some other country.”

Oil and gas industry leaders denounced the lawsuit, calling it naive.

BLM officials said they’re aware of it. “Although we do not provide comment on pending litigation, the BLM has been working over the last several years to update and modernize the rules governing its oil and gas program,” the BLM said in an emailed response to Denver Post queries. “The BLM will continue to work with lessees and operators to implement best management practices and to promote safe and efficient operations and minimize impacts to the environment.”

Physicians for Social Responsibility is backing the lawsuit, which targets 397 Obama administration leases that cover 379,950 acres of public lands in Colorado, Wyoming and Utah. Attorneys said they may broaden the lawsuit to include public land in Montana, New Mexico and other states.

Leases give companies rights to drill and frack. In recent years, public land including terrain in Colorado’s Rocky Mountains and along the Front Range near Denver, in Utah’s red rock canyons and in archaeologically significant areas such as New Mexico’s Chaco Canyon has been leased for industrial development.

“Americans want and expect their public lands to be managed to protect pristine air and crystal-clear water, not creating smog alerts and fracking waste spills,” Dr. Catherine Thomasson, director of Physicians for Social Responsibility, said in a prepared statement. “The health impacts from climate change, from extreme weather events to lethal heat waves, make it clear we must draw the line. We can’t allow this drilling. Its climate health impacts are far too great.”

Obama administration officials have sold leases granting access to an estimated 10 million acres of public land for as little as $2 per acre, the environmentalists say, calculating this is an area larger than Yellowstone, Everglades, Grand Canyon, Olympic, Yosemite, and Great Smoky Mountains national parks combined. They argue that nearly 10 percent of U.S. energy-related pollution of the atmosphere is linked to extraction of oil and gas from public lands.

Gov. John Hickenlooper, on an industry “power lunch” panel Thursday, said he hadn’t reviewed the lawsuit but addressed the issue.

“We see in many cases, with the Department of the Interior, no matter what they do they are going to get sued,” Hickenlooper said.

Western Energy Alliance officials have taken a stand “to remind BLM and the Interior Department” that current federal law requires oil and natural gas leasing to move forward.

“WildEarth is trying to force the government to violate the law,” WEA vice president Kathleen Sgamma said, denouncing “keep it in the ground” actions by environmental lobbyists.

“It’s much easier to just file a frivolous lawsuit than it is to change the law through Congress. The law is on our side, and we agree with Interior Secretary Sally Jewell that these actions to stop domestic energy production are naive.”