Depleted Uranium is a by product of the reprocessing of nuclear energy fuel elements. It consists of Uranium from which much of the isotope useful in nuclear reactors has been extracted for reuse. It is nevertheless radioactive with a long half-life and is also chemically toxic. It is a powerful alpha emitter, which is to say it emits alpha particles, which cannot penetrate through the dead layers of skin but pose a hazard if the substance is ingested or inhaled which is considered "incalculable" by Prof. Doug Rokke, a Pentagon advisor. This substance, depleted Uranium or DU, is not categorised in many jurisdictions as nuclear waste if it can be demonstrated to be useful, and the nuclear industry is eager to find an alternative classification of it where it can. Thus we find it used as ballast and as a counterbalance in civil aviation. The most notorious use of DU is as the tip of armour piercing rounds. The high density of DU - about 1.7 times that of lead - gives it formidable "tank-busting" potential, and its relative cheapness in comparison with the alternative, Titanium, has led to DU being used to tip armour piercing rounds fired from the US A10 "Warthog" jet as well as being used to stabilise Tomahawk cruise missiles and as the basis of armour piercing shells fired by British Challenger tanks. DU shells are manufactured in the UK by Royal Ordnance and in North Carolina by StarMet.

During the Gulf War Britain and the USA used DU-tipped rounds against Iraqi forces. On contact with the target around 20% of the DU is converted into respirable dust. In Iraq the 10-fold increase of cancers, particularly among children, and an increase in birth defects and still births has been correlated with DU contamination, although the MoD has refused to endorse these findings. A report prepared by the UK Atomic Energy Authority for Royal Ordnance plc in April 1991 predicted 500,000 deaths if 50 tonnes of DU were left in the area. DU-tipped shells have twice been condemned by the UN Commission on Minorities and Human Rights as a weapon of mass destruction.

Over 100 Tomahawk missiles have been fired at Serbian targets to date by Britain and the USA. NATO admits that at least 31,000 rounds of DU-bearing ammunition were discharged in the Kosovo conflict. It is thought that as much as 10,000 kg of DU may have been deposited on Kosovo.

The possible effects of DU in Kosovo have been consistently downplayed. On July 13, 1999 Naomi Harley of RAND stated to the Presidential Special Oversight Board when questioned about reports that children in Kosovo were actively playing on the hulks of tanks disabled using DU-tipped rounds "..they could wipe their hands in the dust and lick their fingers and and not have any health problems..." This should be contrasted with instruction sent on December 20, 1990 to Logistics Assistance Representatives (LAR's) deployed to the Gulf theatre. The message advised them on proper assessment, repair and recovery techniques for DU-contaminated equipment - "The number of personnel who take part in the vehicle recovery should be kept at an absolute minimum. They are to be dressed in protective coveralls, gloves and rubberised boots, and they are to also wear the M25 or M17A2 protective mask with M13A2 element and the accompanying head covers (i.e. Mission Oriented Protective Posture [MOPP] level 4). The coverall pant legs are to be worn over the rubber boots and sealed with tape at the ankles. Likewise, the sleeves are to slipped over the gloves and taped. The edges of the hood are to be draped over the coveralls and taped to them and the place where it contacts the respirator. Also, any remaining openings are to be sealed with tape." A similar warning was issued by the MoD to British troops in Kosovo with regard to approaching any object hit by a weapon bearing DU. An internal UN report has been issued to its staff in Kosovo, warning them that the water supply in the warzone may be so contaminated as to be undrinkable. Officials are also warned to steer clear of targets hit with DU-tipped rounds and not to loiter near craters, although "it is impossible to state accurately every location where DU was used." The report also states that even if a solution were to be found, the problem would not be acknowledged, as the cost of cleaning up the DU deposits would run into billions of dollars.

The people of Kosovo can look to Iraq for a grim forewarning of the legacy NATO has left them. Siol nan Gaidheal declares the use of depleted uranium to be a war crime and calls for those responsible for its deployment to be called to account in the Hague.