Depleted uranium has only half the radioactivity of purified uranium, a substance that itself has very weak cancer-causing properties even after prolonged contact. In addition, the seven years since the Gulf War is too short a time for radiation-induced cancers to develop, with the exception of leukemia and thyroid cancer. Uranium, however, does not cause thyroid cancer, and the radioactive particles it emits do not penetrate far enough into the body to affect bone marrow cells, which are the source of leukemia. There is theoretically a cancer risk if a person ingests uranium dust, but the amount required would be huge, said Raymond A. Guilmette, a radiobiologist at Lovelace Respiratory Research Institute in Albuquerque. A recent study of 100,000 such workers from three countries found a slight increase in leukemia and no increase in other forms of cancer.
Inhalation is the other potentially hazardous route of exposure to depleted uranium dust.
Some heavy metals can cause cancer after long or heavy exposures. They include arsenic, beryllium, cadmium, chromium and nickel. However, the war zone in Iraq is not known to be contaminated with those substances. The Iraqi Health Ministry has been quiet about the depleted uranium, content to allow Western groups to criticize the weapons. Ali, the cancer specialist in Basra, acknowledged there may be other causes and that there is no clear proof of a single cause for the cancers.