Depleted Uranium

During the Gulf War, some tanks and munitions containing depleted uranium caught fire or exploded. As a result, a number of military personnel inhaled or ingested depleted uranium. Flying fragments of the material injured others. In its depleted form, uranium is 40 percent less radioactive than in its natural state. The health effects of uranium have been widely investigated, mostly in occupational settings, but the committee found weaknesses in many of these studies. Based on this evidence, it said that no conclusion can be drawn about the effects of depleted uranium and the development of lymphatic or bone cancer; nonmalignant respiratory disease; diseases of the nervous system, gastrointestinal tract, and liver; and other health outcomes. Still, the committee did conclude that there is limited evidence of no association between exposure to uranium and kidney disease, nor between exposure to low levels of uranium and lung cancer. At high levels of exposure, however, the evidence about lung cancer was unclear. The committee recommended follow-up research on veterans with embedded fragments of depleted uranium, and other long-term studies.

Exposure to uranium and depleted uranium

* Under most circumstances, use of DU will make a negligible contribution to the overall natural background levels of uranium in the environment. Probably the greatest potential for DU exposure will follow conflict where DU munitions are used.
* A recent United Nations Environment Programme (UNEP) report giving field measurements taken around selected impact sites in Kosovo (Federal Republic of Yugoslavia) indicates that contamination by DU in the environment was localized to a few tens of metres around impact sites. Contamination by DU dusts of local vegetation and water supplies was found to be extremely low. Thus, the probability of significant exposure to local populations was considered to be very low.
* A UN expert team reported in November 2002 that they found traces of DU in three locations among 14 sites investigated in Bosnia following NATO airstrikes in 1995. A full report is expected to be published by UNEP in March 2003.
* Levels of DU may exceed background levels of uranium close to DU contaminating events. Over the days and years following such an event, the contamination normally becomes dispersed into the wider natural environment by wind and rain. People living or working in affected areas may inhale contaminated dusts or consume contaminated food and drinking water.
* People near an aircraft crash may be exposed to DU dusts if counterweights are exposed to prolonged intense heat. Significant exposure would be rare, as large masses of DU counterweights are unlikely to ignite and would oxidize only slowly. Exposures of clean-up and emergency workers to DU following aircraft accidents are possible, but normal occupational protection measures would prevent any significant exposure.

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Potential health effects of exposure to depleted uranium

* In the kidneys, the proximal tubules (the main filtering component of the kidney) are considered to be the main site of potential damage from chemical toxicity of uranium. There is limited information from human studies indicating that the severity of effects on kidney function and the time taken for renal function to return to normal both increase with the level of uranium exposure.
* In a number of studies on uranium miners, an increased risk of lung cancer was demonstrated, but this has been attributed to exposure from radon decay products. Lung tissue damage is possible leading to a risk of lung cancer that increases with increasing radiation dose. However, because DU is only weakly radioactive, very large amounts of dust (on the order of grams) would have to be inhaled for the additional risk of lung cancer to be detectable in an exposed group. Risks for other radiation-induced cancers, including leukaemia, are considered to be very much lower than for lung cancer.
* Erythema (superficial inflammation of the skin) or other effects on the skin are unlikely to occur even if DU is held against the skin for long periods (weeks).
* No consistent or confirmed adverse chemical effects of uranium have been reported for the skeleton or liver.
* No reproductive or developmental effects have been reported in humans.
* Although uranium released from embedded fragments may accumulate in the central nervous system (CNS) tissue, and some animal and human studies are suggestive of effects on CNS function, it is difficult to draw firm conclusions from the few studies reported.