Earle Dixon, the Bureau of Land Management's former project manager, takes radiological readings in February 2004 at the Anaconda Mine in Yerington. A judge has ruled that Dixon was fired because he refused to stop speaking out about dangers posed there by radioactive and other toxic wastes. Photo by The Associated Press

RENO -- After years of delay, federal regulators have ordered Atlantic Richfield Co. to take the first major step toward cleaning up contamination at an abandoned copper mine in Northern Nevada that they say poses an "imminent and substantial" threat.

The U.S. Environmental Protection Agency's order to determine the extent of the contamination replaces voluntary cleanup efforts and is the most significant to date at the half-century old Anaconda Co. mine, EPA officials said Wednesday.

The order stems primarily from studies in 2003 that found the soil and groundwater had been contaminated with uranium, apparently a radioactive byproduct of decades of chemical processing of copper at the mine site that covers six square miles.

The mine also is polluted with arsenic, beryllium, lead, mercury and selenium

BLM spokesman Richard Brown said the agency had no comment on the new order.

The potential Superfund site borders the town of Yerington and is near the Yerington Paiute Tribe Reservation, about 60 miles southeast of Reno.

Cleanup plans have been the source of contentious negotiations between EPA officials, the Bureau of Land Management, the state of Nevada, Atlantic Richfield, neighboring residents and tribes.

An administrative law judge for the U.S. Labor Department ruled in September that a former BLM manager at the site, Earle Dixon, was illegally fired for speaking out about dangers at the mine.

Dixon reported unsafe levels of uranium he claims state regulators knew about but covered up since 1984.

Dixon claims he was fired after he complained about what he said was a cover-up of the health and safety risks at the toxic mine.

The BLM is appealing the law judge's ruling.

Atlantic Richfield officials said they were caught by surprise by the order, which was signed Friday but not made public until late Tuesday.

The company has been "negotiating with EPA for months" on a voluntary agreement to do the "same scope of work," said Cindy Wymore, a spokeswoman for Atlantic Richfield's parent, BP.

"We were ready to sign off on an agreement to do that work. EPA had the paperwork," she said by telephone from Yerington. "We don't know if it is posturing or what."

Wymore said EPA officials want to add the site to the U.S. Superfund list over the objections of Atlantic Richfield and the state of Nevada.

Officials for the Nevada Division of Environmental Protection had not seen the order, and spokesman Dante Pistoni would not comment.

EPA officials said the new action does not put the site on the Superfund list, nor is the agency seeking such status, though it remains an option.

"This lays out the road map for how to investigate the entire site, look at what kind of contamination is out there, what kind of risk we have out there, and what to do to clean it up," said Jim Sickles, EPA's remedial project manager at the site.

Kathleen Johnson, chief of EPA's Superfund branch managing the site, said the study the agency ordered "is a necessary step in addressing imminent and substantial threats from hazardous substances."

Local residents and environmentalists primarily blame Atlantic Richfield for the slow pace of cleanup efforts at the mine, which closed for good in January 2000.

Vince Conway, chairman of the Yerington Paiute Tribe, and others said they've been concerned about the quality of the company's proposed plans and are glad to see EPA taking action.

"We think that ARCO has failed to move ahead on the site with enough urgency and are supportive of the EPA's efforts to speed up the remediation," added Dan Randolph, executive director of the Great Basin Mine Watch, a nonprofit watchdog group based in Reno.

A group of concerned citizens organized by a woman who lives across the street from the mine site, Peggy Pauly, also applauded the move.

"We feel EPA has been too patient," the Yerington Community Action Group said in a statement.

Sickles confirmed EPA has been discussing a voluntary agreement with Atlantic Richfield since June, and "we actually have been getting some forward motion from those folks."

"But the agreement is set to start the first of February and the idea was to go ahead and ensure we could get a workable deadline for all parties involved so this moves ahead," he said.

Sickles said if a voluntary agreement is reached by the end of the month, it would replace the formal order.

"That is better for all parties. If not, this is another way to make it happen," he said.

Actual cleanup of the site is expected to take several years and cost tens of millions of dollars.

"The investigation alone we are estimating will take three to five years, and that doesn't get you to the remedy. That just gets you to where you know what the remedy is," Sickles said.

Work at some similar sites goes on for decades, he said.

The Yerington site is especially complicated because it's so big and has radiological contamination in addition to the usual heavy metals and acid drainage.

"It's definitely what they call a 'megasite,' which means cleanup will probably be more than $50 million," Sickles said.