An air tanker crashed Sunday while dropping retardant on a wildfire in Utah, killing the two pilots aboard, officials said. The Lockheed P2V, operated by Neptune Aviation of Missoula, Mont., went down shortly before 2 p.m. while working the White Rock fire in the Hamblin Valley area west of Cedar City, KCSG-TV, Cedar City, reported. The Iron County Sheriff\'s Office identified the two pilots as Capt. Todd Neal Tompkins, 48, and First Officer Ronnie Edwin Chambless, 40, both of Boise, Idaho. The cause of the crash had not been determined, the TV station said. The U.S. Bureau of Land Management said the White Rock fire was ignited by lightning Friday night near Caliente, Nev., and spread into Utah, burning about 5,000 acres by Saturday, WSL-TV, Salt Lake City, reported.