So it is naturally occuring and is made into things.

Don and I have had this discussion before. He quotes the Seattle Post Intelligencer, here is what the World Health Organisation has to say about it - Source WHO - Depleted Uranium - Fact Sheet No: 257 last updated January 2003:

Applications of depleted uranium:

Due to its high density, about twice that of lead, the main civilian uses of DU include counterweights in aircraft, radiation shields in medical radiation therapy machines and containers for the transport of radioactive materials.

The military uses DU for defensive armour plate.
DU is used in armour penetrating military ordnance because of its high density, and also because DU can ignite on impact if the temperature exceeds 600°C.

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.


Intake of depleted uranium:
Average annual intakes of uranium by adults are estimated to be about 0.5mg (500 ìg) from ingestion of food and water and 0.6 ìg from breathing air.
Ingestion of small amounts of DU contaminated soil by small children may occur while playing.
Contact exposure of DU through the skin is normally very low and unimportant.
Intake from wound contamination or embedded fragments in skin tissues may allow DU to enter the systemic circulation.

Absorption of depleted uranium:
About 98% of uranium entering the body via ingestion is not absorbed, but is eliminated via the faeces. Typical gut absorption rates for uranium in food and water are about 2% for soluble and about 0.2% for insoluble uranium compounds.
The fraction of uranium absorbed into the blood is generally greater following inhalation than following ingestion of the same chemical form. The fraction will also depend on the particle size distribution. For some soluble forms, more than 20% of the inhaled material could be absorbed into blood.
Of the uranium that is absorbed into the blood, approximately 70% will be filtered by the kidney and excreted in the urine within 24 hours; this amount increases to 90% within a few days.

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.

Don has previously referred to Southern Iraq and the "Desert Storm" camapaign as the indicator of the evils of DU ammunition. Before I referred him the a UK member of the European Parliament and her efforts on behalf of the Maadan (Iraq's Southern Marsh Arabs) who were then refugees living in the South West of Iran. They can verify that it was not Coalition Forces that peppered them with DU ammunition, Saddam's helicopter gunships did a fair job, but that really is neither here nor there, the real damage inflicted on the area by Saddam's regime was the deliberate draining of the marshes and the deliberate poisoning of the water courses in areas where drainage was not possible. That Don is where the main cause behind the medical evidence in Southern Iraq lies - nothing to do with DU ammunition.