IDAHO FALLS — The nation's worst fire season in four years grew worse Friday as yet another of the nation's nuclear facilities was threatened and hundreds were evacuated.
The 18,000-acre blaze near the Idaho National Engineering and Environmental Laboratory began Thursday and was fanned by 28 mph wind gusts.
Some 1,800 employees were ordered out of three buildings at the sprawling eastern Idaho complex as a precaution, said Jason Bohne, a lab spokesman. There were no injuries.
No widespread damage has been reported at the 890-square-mile facility, but Bohne said a small fire "went into" a reactor test area before that section of the fire was contained. The fire affected only a grassy section of the fenced-in area and did not damage any buildings.
Decreasing winds during the night gave fire crews the upper hand, and only about 50 firefighters remained in the area Friday, mopping up hot spots.
The blaze was the third to threaten a facility with nuclear material in as many months. Fire struck the Los Alamos National Laboratory in New Mexico in May, and a huge fire swept across the Hanford nuclear reservation in southeastern Washington last month.
Both raised concerns about the release of radioactive material, from rain washing contaminated soil into New Mexico's streams to airborne particles in Washington state.
The only damage to the Idaho facility was the destruction of 52 power poles that will have to be replaced by the local utility. Officials said most workers at the facility were back on the job Friday.
But the situation was not as good elsewhere in eastern Idaho, where wildfire has already blackened over 200,000 acres this month. Only skeleton crews are manning the largest blazes since fire activity throughout the West has stretched resources to the limit.
"We're spread really thin," a dispatcher for the Eastern Idaho Interagency Fire Center said. "We have about 50 fires going right now, and we don't have the manpower for all of them."
Gov. Dirk Kempthorne signed a 30-day emergency proclamation making state resources like National Guardsmen and equipment available to local communities to help suppress wildfires.
Near Salmon, in the Salmon-Challis National Forest, the Clear Creek Fire escaped containment lines on the south and raced over another 25,000 acres on Thursday. As the largest fire in the nation, the Clear Creek Fire has charred an estimated 79,000 acres.
"It is a very difficult fire," spokesman Bill Beebe said. Fire behavior was so erratic Thursday afternoon that firefighters were pulled off the line for safety reasons.
The Twin Fire, also in the Salmon-Challis National Forest, reached 430 acres. Steep terrain was challenging suppression efforts. No target date for containment has been set.
Elsewhere, there were also evacuations in California, where a fire has blackened 19,000 acres of the Sequoia National Forest, creeping up to several homes on the forest's borders early Friday. More than 100 residents were forced to evacuate the area 120 miles north of Los Angeles. No injuries have been reported.
The fire season is the worst since 1996. More than 59,000 fires have burned 3 million acres, according to the National Interagency Fire Center in Boise. Four years ago, the total was 3.1 million acres by this date.
For the first time since then, the fire center has called in Army soldiers for training and eventual posting on the fire lines. Elite hotshot firefighting crews, air tankers and helicopters are in big demand.
Firefighters, meanwhile, have made progress against two huge fires in Colorado and Montana.
In Mesa Verde National Park, Colo., a 40-mile fire line was keeping a 23,000-acre wildfire from spreading. The fire in the nation's largest archaeological preserve was 70 percent contained late Thursday, fire spokesman Bobby Kitchens said.
Park Superintendent Larry Wiese said the park could reopen next week. Its well-known attractions — Balcony House, Cliff Palace, Spruce Tree — have not been damaged.