Friday April 25, 2003 -- THE GUARDIAN, London
Soldiers returning from the Gulf will be tested for depleted uranium. Alok Jha explains what the metal is and the dangers associated with it
What is it?
Depleted uranium is a toxic heavy metal. It is a by-product of the nuclear fuel and weapons industries.
Where does it come from?
Naturally occurring uranium is a mixture of two different kinds - uranium 235 and uranium 238.
Uranium 235 is by far the most radioactive kind. Unsurprisingly, this is the one that the nuclear fuel and weapons industries try to extract from the naturally occurring metal. When extracted it called "enriched uranium". This is what is used in fuel rods and nuclear weapons.
What is left over after the extraction process is called "depleted uranium". It is still a mixture of the two kinds (or isotopes) of uranium, but it is mainly made up uranium 238.
Who is using it in weapons?
The Americans and British have used vast amounts in both the recent and the last Gulf wars. They also used it in the Balkans.
How does a depleted uranium weapon work?
The use of depleted uranium in weapons has little to do with its hint of radioactivity, and everything to do with its high density. It is one of the more dense elements and that means a shell going at a particular speed carries an awful lot of momentum. It is that momentum which is useful.
Depleted uranium is nearly two-and-a-half times more dense than steel and more than one-and-a-half times more dense than lead. This means that a typical 2ft-long missile tipped with depleted uranium and weighing just under 5kg has enough momentum to break through the heavy armour of a tank. Once it has blasted through the armour, the uranium tip disintegrates. Because of the heat created, the particles of depleted uranium start burning.
What does it do to the soldiers under attack?
This is not pretty - the immediate effects of this weapon on a tank's crew will almost certainly be devastating. Aside from the shards of metal flying around, there is a danger of being burned or suffocating as the oxygen inside the vehicle is used up.
What about future contamination?
Longer-term damage to both people and the environment has been the subject of several studies in the past few years.
For soldiers working with, or attacked by, depleted uranium weapons, a long-term risk is simply the toxicity of the metal - rather than its radioactivity.
But a study conducted by the Royal Society last year concluded that the majority of soldiers and civilians in the last Gulf war were not exposed to levels of depleted uranium likely to cause what is known as heavy-metal poisoning.
What happens if it gets inside you?
Things are different if DU gets into your lungs or bloodstream; then the radioactivity is a factor.
Soldiers breathing in the dust created by a burning depleted uranium tip, for example, may end up with radioactive deposits of the metal in their lungs. The Royal Society study suggested that one in 1,000 soldiers who had had a large intake - eg been in a tank that was attacked with a depleted uranium missile - will die of lung cancer as a direct result of the radioactivity.
This compares to a lifetime risk of fatal lung cancer in the general population of about one in 250 for non-smokers. That means if 1,000 non-smokers are exposed to depleted uranium in heavy doses, five would die of lung cancer - rather than four if none had been exposed.)
Why have there been more concerns recently?
A recent study in Germany suggested that uranium molecules can travel to every part of the body, including to the sperm and eggs and that this increases the probability of cancer and damage to genes.
Soldiers who claimed to have been exposed to depleted uranium in the first Gulf war reported that their children had been born with deformed ears and toes and some suffered from bladder problems.
Though the work was peer-reviewed, many scientists have dismissed the study as unscientific and not being properly thought out. Opponents argue that the damage could have been the result of exposure to one of many dangerous chemicals that exist on a battlefield.
Can exposure be tested?
Depleted uranium can be detected by testing urine samples. The Ministry of Defence will be testing soldiers who believe they have been exposed to depleted uranium.
If they test positive, they will be able to have follow-up checks on their kidneys, as the metal tends to concentrate there and may affect its function.
How would civilians be affected?
Civilians would probably encounter depleted uranium after a battle and would be spared large doses.
Their problems would come from the possible contamination of food and water supplies. If these are affected, it is possible the depleted uranium will spread far from where it was initially used. The actual remnants of any missile can also remain in the ground for long periods of time and would remain potentially dangerous to anyone who ingested the pieces even decades later.
At present, the evidence suggests that there is little to worry about unless the metal is actually inside a person. However, the absolute risks are unknown and it may take decades of monitoring before we know how bad the problems are.
As it stands, smoking cigarettes will kill you far more quickly than being exposed to depleted uranium.