The sun shines through the smoke from the Las Conchas wildfire near the Los Alamos National Laboratory in Los Alamos, New Mexico, June 29, 2011. The New Mexico wildfire raged largely unchecked for a fourth day near one of the nation's top nuclear arms production plants on Wednesday, but firefighters finally gained some ground in corralling the flames.  

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.