The Grand Canyon Trust, an environmental group, has sued the operator of America’s last conventional uranium processing mill, saying its vast piles of spent ore and radioactive waste emit dangerous levels of radon and other toxins that violate the Clean Air Act.

The group and other critics of the White Mesa Mill near Blanding, Utah say it is a poorly disguised nuclear waste dump that would have gone out of business long ago were it not propped up by a lucrative federal contracts.

The uranium market has declined in the wake of the Fukushima meltdown. To stay alive in a depressed market, Energy Fuels Resources, the mill’s operator, recycles mine tailings and radioactive waste — known as “alternate feed” — from Superfund sites around the country. The mill extracts any remnants of uranium from the waste then sells the concentrated, purified uranium, called yellowcake, to its customers, some of which are government-owned utilities obligated to buy White Mesa yellowcake at prices far higher than the $35 a pound it is currently fetching on the spot market. The leftover waste, a toxic stew of industrial chemicals, is stored in open pits called impoundments.

Energy Fuels spokesperson Curtis Moore said the issues raised in the lawsuit “are either inaccurate or have already been addressed through the proper regulatory channels.”

Taylor McKinnon of the Grand Canyon Trust says he hopes the lawsuit will “rip the mill from the rat’s nest of bureaucrats who have been protecting the status quo.”

The mill, he and other critics contend that uranium mining, milling and cleanup has become a virtual cottage industry — one orchestrated largely by the federal government.

During the Cold War period of 1940s through the 1980s, uranium was mined extensively in the Colorado Plateau to supply critical materials for the nation’s nuclear weapons program. The U.S. Department of Energy manages the nation’s surplus uranium and much of the cleanup of old processing mills.

Travis Stills, an energy and conservation law attorney, argues that the DOE’s mandate to “provide a domestic supply of uranium” is outdated and wreaks havoc on environmental and human health. He also says it’s unnecessary. The DOE already owns a uranium stockpile worth $7 to $8 billion.

The DOE doesn’t want to sell off the stockpile, Stills argues, because that would drive uranium prices down. Instead, the government artificially inflates prices to keep the industry going, he says.

Energy Fuels also operates several mines at the Grand Canyon, despite the federal ban on uranium mining there, because it possesses old mining claims that were “grandfathered in.” The company said in December it planned to shutter its Pinenut Mine there as well as the White Mesa Mill in 2014 and potentially reopen them in 2015. It reversed that decision last month and announced it would continue mining, but stockpile the ore pending better market conditions.

Cleaning up uranium is not cheap. The DOE is spending a billion dollars to dispose of tailings at an enormous site near Moab — a cost “born by the taxpayer,” the Trust’s lawsuit points out. On the Navajo reservation alone, there are 500 abandoned uranium mines. The EPA estimates the cleanup cost would be in the hundreds of millions. An $18 million bond has been posted for cleaning up White Mesa Mill when it stops processing uranium — not nearly enough, Stills argues. He says the federal government — and the taxpayer — will be left holding the bag for that cleanup too.

Indeed, the DOE is slated to inherit White Mesa Mill for cleanup. Stills says that the department’s mission, to at once promote uranium mining and oversee its cleanup, is contradictory but that it keeps the agency employed. “It’s bureaucratic make-work,” he says. “As long as they keep making a mess, they’ll need to keep cleaning it up.”