UK troops returning from Iraq are to be offered tests to check for traces of depleted uranium (DU) in their bodies.
The Ministry of Defence (MoD) announced the screening programme after concerns were raised about the effects of exposure to DU, including a possible greater risk of cancer or kidney damage.
Britain's leading scientific body - the Royal Society - claimed soldiers and civilians might have been exposed to dangerous levels of the heavy metal.
The MoD said it had decided last year to offer urine tests to personnel returning from deployments where DU ordinance was used.
On Thursday, the United Nations said people in Iraq needed urgent advice on avoiding exposure to DU.
It is the substance left over after ordinary uranium has been enriched for use in nuclear weapons or reactors and is used to make armour-piecing shells.
An MoD spokesman said that troops were being offered the tests only as a precaution.
He said the problems DU might pose were only likely to be very localised.
The MoD argues that the particulates produced by the weapons travel only very short distances.
The Royal Society tackled claims by Geoff Hoon that DU was not a risk, the Guardian said.
Professor Brian Spratt FRS, chairman of the society's DU working group, said: "It is highly unsatisfactory to deploy a large amount of material that is weakly radioactive and chemically toxic without knowing how much soldiers and civilians have been exposed to it."
Milk and water
Professor Spratt called for urine samples to be taken from a cross-section of soldiers.
He also said that long-term monitoring of milk and water supplies in Iraq were necessary to monitor the health effects on civilians.
The tests will be available to any of the 45,000 British servicemen and women returning from the Gulf.
The MoD is said to be planning to publish details of where and how much DU was used, as well as the results of the tests.