 Michael Thun, head of epidemiological research at the American Cancer Society, cautioned that the variations in the rates could be attributed to chance, given the small population on Vieques.A 2000 Nuclear Regulatory Commission report concluded that "the public had not been exposed to depleted uranium contamination above normal background (naturally occurring) levels".Surveys of the wreckage of a target ship in a shallow bay at the bombing range, however, revealed its identity to be that of the , a target ship in nuclear tests in the Pacific in 1958.