* Nuclear weapons lab closes due to fire danger
* Fire has potential to double or triple in size (Recasts; adds suspected cause, details throughout)
By Zelie Pollon
LOS ALAMOS, N.M., June 28 (Reuters) - New Mexico fire managers scrambled on Tuesday to reinforce crews battling a third day against an out-of-control blaze at the edge of one of the nation’s top nuclear weapons production centers.
The fire’s leading edge burned to within a few miles (kilometres) of a dump site where some 20,000 barrels of plutonium-contaminated waste is stored at the Los Alamos National Laboratory, fire officials said.
Officials for the government-run lab said the stored waste is considered low-level radioactive material and remains a safe distance from the fire in an area cleared of trees and other vegetation.
Carl Beard, director of operations for the lab, said there has been no release of radioactive or hazardous materials into the environment and there was no immediate threat to public safety, “even in these extreme conditions.”
The fire, believed to have been ignited Sunday by a fallen power line, has consumed nearly 61,000 acres (24,580 hectares) of thick, pine woodlands in the Santa Fe National Forest, which surrounds the lab complex and adjacent town of Los Alamos on three sides.
Tucker said he feared the so-called Las Conchas Fire, whipped by high, rapidly shifting winds, could soon double or triple in size.
“I seriously believe it could go to 100,000 acres (40,470 hectares),” he said at a news briefing. “We have fire all around the lab. It’s a road away.”
A small offshoot of the blaze jumped State Highway 4 onto the lab grounds on Monday, burning about an acre of property before it was extinguished about two hours later.
More than 300 firefighters, backed up by a fleet of seven water-dropping helicopters, battled the blaze, as fire managers scurried to bring in additional ground crews.
Lab officials also called in teams late Monday to monitor air quality, with high-volume air samplers ready to deploy. Hundreds of National Guard troops have been dispatched to back up law enforcement in the area.
Both the town of Los Alamos, home to about 10,000 residents, and the laboratory, with a work force of about 12,000 people, were evacuated on Monday, and the lab will remain closed at least through Wednesday, officials said.
Situated on a hilltop 35 miles (56 km) northwest of Santa Fe, the lab covers 36 square miles and includes about 2,000 buildings, none of which has yet burned.
Established during World War Two as part of the top-secret Manhattan Project to build the first atomic bomb, it remains one of the leading nuclear arms manufacturing facilities in the United States.
Nuclear Watch New Mexico said on its website its greatest concern was for the 20,000 55-gallon sealed drums of plutonium-tainted waste stored at one corner of the complex, some stacked in the open on asphalt, some in tents, some buried underground.
Fire officials say if the blaze did manage to reach the area, they would use fire-retardant foam to douse the flames. (Writing by Steve Gorman; Editing by Jerry Norton)