Depleted uranium is a mildly radioactive substance. Depleted uranium shells are not sufficiently radioactive to be classified as a "radiological weapon". Tank crews firing the rounds are reported to receive the equivalent of a chest X-ray each day. Fresh-from-the-factory DU tank shells are normally handled with gloves, to minimise the health risk, and shielded with a thin coating. The alpha particle radiation emitted by DU travels less than an inch and can be stopped by cloth or even tissue paper. However, the health risk becomes much greater once the projectile has been fired. When the DU material burns (usually on impact; or as a dust, it can spontaneously ignite) protective shields disappear and radioactive oxides are produced that can be inhaled or ingested. Once inside the body, the toxic oxide dust that emits alpha particles that they can destroy cells in soft tissue. In addition to its radioactivity, uranium is chemically toxic, like lead, and can damage the kidneys or lungs. Children are especially vulnerable because their cells divide rapidly as they grow. In pregnant women, absorbed uranium can cross the placenta into the bloodstream of the foetus and cause child deformity or abortion.
Natural uranium ore from the mine goes through an enrichment process designed to separate uranium 235 (U-235), the isotope used for nuclear weapons and nuclear reactors, from uranium 238 (U-238), a low-level radioactive by-product. The highly radioactive isotope U-235 accounts for less than 1% of mined uranium; nearly all the rest is U-238. The vast quantity of highly toxic metal (U-238) generated by this process is called "depleted uranium" or DU. DU emits primarily alpha radiation, and its half-life is thought to be about the age of the Earth, or 4.5 billion years.
DU is approximately 2.5 times denser than iron and 1.7 times denser than lead. This high specific gravity means that, as a projectile fired from a tank or aircraft, it carries enough kinetic energy to blast through the tough armour of a tank. Furthermore, the impact of this penetration generates extreme heat. DU is pyrophoric, meaning that it burns on impact and can set the target on fire. DU is easy to process and endless quantities can be obtained free from the Department of Energy (DOE), which controls DU and considers its use in munitions to be "utilization of waste material."< Depleted uranium penetrators were developed by the Pentagon in the late 1970s as anti-tank, armour-piercing projectiles. The depleted uranium, which makes up the shell's core, is a radioactive by-product of the enrichment process used to make atomic bombs and nuclear fuel rods. The material is extremely hard and abundant and provided free to weapons manufacturer by the nuclear industry. When fired, the core bursts into a searing flame that helps it pierce the armour of tanks and other military targets. Diesel vapour inside the tank are ignited and the crew is burned alive.
On explosion, the shells release a deadly radioactive aerosol of uranium. It can kill everyone inside a tank. This ceramic aerosol can travel in air tens of kilometers from the point of release or be stirred up in dust and re-suspended with wind or human movement. This radioactive ceramic can stay deep in the lungs for years, causing emphysema and/or fibrosis. It can also initiate or promote cancers, do damage to the gastro-intestinal tract, and it can affect the blood which is the basis of the immune system.
DU began accumulating in the USA in the early 1940s while the Manhattan Project was developing the first atomic bombs. To date, more than 500 thousand tons have been produced, and it continues to accumulate. At the uranium enrichment plant in Paducah, Kentucky, and two other locations, DU is packed into metal containers and stored outdoors.
Production of DU missiles began in the 1970s and 1980s at a number of military munitions factories. The weapons are tested at several firing ranges around the country.
The US military first used DU munitions in combat during the Gulf War, firing penetrators from 120 and 105mm canons mounted on tanks. Aircraft fired them from 25 or 30mm guns. The British fired DU rounds from tanks only. During Operation Desert Storm (24 - 28 February 1991), at least 10,000 rounds of DU ammunition were fired from tanks, and at least 940 thousand were fired from aircraft. At least 40 tonnes of depleted uranium was dispersed in Iraq and Kuwait in this way, considered sufficient to cause tens of thousands of potential deaths. It may have contaminated soil and drinking water. Doctors wonder if the fatal epidemic of mysterious stomach diseases and swollen abdomens amongst Iraqi children is caused by kidney failure resulting from uranium poisoning, made worse by malnutrition and poor health conditions. UN personnel and aid workers have seen children playing with empty shells, abandoned weapons and destroyed tanks. One child was using depleted uranium shells as hand puppets. Six American vehicles struck with DU "friendly fire" were deemed to be too contaminated to take home, and were buried in Saudi Arabia. Of 16 more brought back to a purpose-built facility in South Carolina, six had to be buried in a low-level radioactive waste dump.
The Pentagon has traditionally been tight-lipped about DU. Official figures on the amount used were not released for years after the 1991 Gulf War and Bosnia conflicts, and nearly a year after the 1999 Kosovo campaign. There are no official figures for DU use in the latest war in Iraq (2003).
The NATO announcement of March 1999 that it was using such shells in Kosovo has been condemned by international human rights groups.