Nearly 80 rail cars loaded with contaminated sand from Kuwait are headed toward a dump in southwestern Idaho. American Ecology Corp. is shipping about 6,700 tons of sand containing traces of depleted uranium and lead to a hazardous waste disposal site 70 miles southeast of Boise. The company has previously disposed of low-level radioactive waste and hazardous materials from U.S. military bases overseas at facilities in Idaho, Nevada and Texas, said American Ecology spokesman Chad Hyslop, who is based in Boise. As you can imagine, the host countries of those bases don't want the waste in their country," Hyslop said. Neither do leaders of the Snake River Alliance, a nuclear watchdog group, who have vowed to monitor the site. "Depleted uranium is both a toxic metal and a radioactive substance," said Andrea Shipley, the group's executive director. "That is a concern." The sand coming to Idaho from Camp Doha, a U.S. Army Base in Kuwait, was contaminated with uranium after military vehicles and munitions caught fire during the first Iraq war in 1991. Depleted uranium, twice as dense as lead, has been used as a component in armor plating to protect tanks and for armor-piercing projectiles. American Ecology operates the only commercial hazardous waste disposal site in Idaho on 1,100 acres of land in the Owyhee desert. Disposal operations cover 100 acres in the middle of the property, Hyslop said, and about a third of the material disposed at the Idaho site is from the U.S. military. The company disposed of uranium-contaminated Bradley fighting vehicles there in 2006.