U.S. Hypocrisy

In January U.S. Secretary of Defence, Donald Rumsfield, said that the U.S. had found radiation in Afghanistan - but that it was from DU warheads belonging to Al-Qaeda. U.S. officials say that uranium-238 found in an al-Qaeda facility in Afghanistan was intended for "dirty bombs" that would "spread radioactive material over a wide area. In addition to killing people in the bomb blast and poisoning others with radiation such a bomb could render large areas unusable and require lengthy and expensive clean-up efforts."
The U.S. has done exactly this with uranium-238 in bombing Iraq in 1991 (320 tons of U-238), Bosnia in 1995 (3 tons), and Kosovo in 1999 (10 tons). But when the U.S. Air Force uses U-238, it is called "depleted uranium."
When the UN General Assembly was asked on November 29th to study the effects, in Iraq, of radiation from the U.S. U-238 bombardment, the U.S. lobbied so strongly against the resolution that it failed 45 to 54 with 45 abstentions.
For 12 years the Pentagon has claimed that U-238 weapons don't poison the earth or cause cancer. Why then is the U.S. so opposed to studying its effects? How can the US call the threat of U-238 by others an act of terror without condemning its own Air Force?