Iraqi health officials contend that depleted uranium was used for the first time on American and British armaments during the 1990-91 Gulf War. They say there has been a marked increase in cancer from what they say was low-level radioactive and toxic dust that billowed out of the explosions. A study conducted by a group called Swords to Plowshares and the National Gulf War Resource Center, concluded that thousands of allied troops may have been exposed to the uranium dust by clambering over damaged Iraqi vehicles after the war.