Smoke from the Pacheco Canyon Wildfire
Los Alamos National Laboratory (LANL) in New Mexico will remain closed through Thursday, June 30 as the Las Conchas Fire is threatening the nuclear lab. REUTERS

The wildfire threatening to consume nuclear waste stored at Los Alamos National Laboratory is poised to become New Mexico's biggest ever, burning nearly 94,000 acres by late Thursday.

Strong winds have fed the fire as it blazes through the Santa Fe National Forest and Valles Caldera National Preserve, thrusting more than 1,200 firefighters into a desperate fight to contain the flames.

We're seeing fire behavior we've never seen down here, and it's really aggressive, Los Alamos County Fire Chief Douglas Tucker told reporters.

Chief among their concerns is the Los Alamos lab, the birthplace of the nuclear bomb and a site that continues to design and test nuclear weapons in its role as one of the nation's preeminent scientific research facilities. Firefighters cleared brush and other flammable material away from about 20,000 barrels of plutonium-contaminated waste. Lab officials said that most of the radioactive waste at Los Alamos is sealed in fire-resistant steel drums that are placed on concrete floors.

The threat is pretty limited, said Kevin Smith, the U.S. Department of Energy's site manager for Los Alamos, in reference to waste that had been buried underground. Most of the materials have been dug up.

The blaze also consumed sacred Native American sites at the Mescalero Apache Reservation.