An expert on depleted uranium (DU) has raised doubts over the tests being offered to UK soldiers returning from Iraq who think they may have been exposed to the material on Iraqi battlefields.
The Ministry of Defence (MoD) announced the voluntary screening programme after concerns about the effects of breathing in the radioactive material, including a possible greater risk of cancer.
Malcolm Hooper, an emeritus professor of medicinal chemistry on the British Government's DU Oversight Board, said the test, which looks for high levels of uranium in veterans' urine, would not necessarily expose DU.
He told BBC Radio 4's File On 4 programme: "Uranium testing is not going to discover depleted uranium. It's not an approach that's valid scientifically."
Professor Hooper's argument focuses on the fact that uranium is soluble and easily excreted, whereas a DU explosion sends insoluble ceramic particles into the air.
"It's fine particles that get deep into the lungs and stay perhaps for ever that we're worried about," he says.
He is also critical of the MoD's decision to test only volunteers rather than a group from all parts of the theatre of war.
The MoD, however, has said all troops were given instructions about how to protect themselves from DU on the battlefield.
Its safety guidance to armed forces says they should reduce time spent close to stocks of DU munitions and avoid areas contaminated by DU oxide dust.
But File On 4 has learned that in some cases, this advice was not followed.
Alan Hopkins, who was in Basra as a member of the Territorial Army, says during his training in Germany, with about 70 other soldiers, DU was never mentioned.
His platoon recovered Iraqi tanks that had come under fire, although they never knew for certain whether DU was involved.
"One of the crews was half way through dragging an Iraqi tank up when a German TV crew pulled up and said, 'You realise we've just tested that for DU contamination and told them it's positive.'
"Also, a British medical colonel pulled up to one of the crews and started jumping up and down, saying, 'Who's told you to clean that? None of them have been cleared'."
Alan Hopkins claims he had none of the protective clothing recommended by the MoD. It was only when he returned home that he discovered on the internet what protection he should have got.
In an interview for the programme, the Defence Minister Lewis Moonie insisted that all troops were given adequate training and had the necessary protective equipment.
"Anybody who was definitely going into a situation where DU was either being used or had been fired would have been given the briefing and would know what to do."
Listen to this edition of File On 4 on Sunday 8 June at 1700 BST.