(AP) -- With firefighters holding their ground against the largest wildfire ever in New Mexico, officials at the nation's premier nuclear weapons laboratory and in the surrounding city planned for the return of thousands of evacuated employees and residents.
The blaze was several miles upslope Friday from Los Alamos National Laboratory, boosting confidence that it no longer posed an immediate threat to the facility.
Thousands of experiments, including those on two supercomputers and studies on extending the life of 1960s-era nuclear bombs, have been put on hold because of the fire.
"I anticipate that we are going to be able to bring the laboratory back up in a way that's smooth and continues to maintain the safety and security that we're responsible for," Lab Director Charles McMillan said.
Authorities didn't give a timetable for when they would lift evacuation order that began Monday for the town of Los Alamos, home to 12,000 people. But some county workers were already back to prepare for the eventual rush of utility service calls, as well as possible flooding from surrounding mountainsides denuded by the wildfire.
Joe Reinarz, a fire official who had also worked at one of the large Arizona wildfires this season, said the fire did not grow significantly on Friday and that containment lines were holding but were no guarantee.
"Everything we've seen this summer doesn't indicate that an old fire is going to stop much. It's unusually dry in the Southwest," he said.
The fire has blackened more than 162 square miles in the last six days, making it the largest in New Mexico history. Erratic winds and dry fuels helped it surpass a 2003 fire that took five months to burn through 94,000 acres in the Gila National Forest.
A key challenge Friday was stopping the flames from doing more damage to the lands of Santa Clara Pueblo. The fire had made a run north toward the reservation earlier this week, hitting the pueblo's watershed and cultural sites.
Santa Clara wasn't the only Indian community feeling the effects of the fire. To the south, Cochiti Pueblo was also worried about damage to ground cover affecting its watershed.
Also, the Pajarito Plateau has hundreds of archaeological sites at Bandelier National Monument that hold great significance to area tribes. About half of the park has burned, Bandelier superintendent Jason Lott said.
"The impact to our pueblos is unprecedented," said U.S. Rep. Ben Ray Lujan, D-N.M.
More than 1,200 firefighters were on the lines trying to slow down the flames as National Guard troops, state police officers and deputies patrolled neighborhoods and enforced evacuation orders.
Fire operations section chief Jerome Macdonald said parts of the fire in Santa Clara canyon burned hot while other areas saw less damage because of overnight temperatures and lighter winds.
In Los Alamos, fire officials said that crews worked to keep flames from spreading down a canyon that leads to the lab and the town. Los Alamos Fire Chief Doug Tucker said a small fire lit to remove fuels was steadily burning and being monitored by 200 firefighters.
The canyon runs past the old Manhattan Project site in town and a 1940s-era dump site where workers are near the end of a cleanup project of low-level radioactive waste, as well as the site of a nuclear reactor that was demolished in 2003.
Most of the town's displaced residents have been staying with friends or family. The American Red Cross has set up two shelters where 110 people have been staying.
Evacuees at the shelter at the Santa Claran Hotel Casino in Espanola, about 20 miles from Los Alamos, said the first night was the most difficult because of the commotion of people settling in and getting used to sleeping in a room with dozens of strangers.
"Being alone in my apartment, I know what sounds it makes. My refrigerator kicks on, I hear the footsteps in the hallway. I'm used to that," said Michael Calloway, who took shelter at the casino. After two nights, the evacuees said they have a rhythm that for Cynthia Springer includes picking a spot away from a loud snorer.
"I don't know if I snore," said evacuee Scott Jonze, who lives alone in his apartment in Los Alamos. "But my cat can tell you."
Santa Claran shelter manager Don Hughes said that about 30 people who spent the first night there have found other places to stay.
Explore further: US-backed drug spraying triggers health fears in Colombia