Sir, - There has been much discussion of the environmental effects of depleted uranium on soldiers and civilians in Kosovo and the Persian Gulf. Most public concern has centred on DU's radioactivity and its supposed implication in diseases such as leukaemia, which are known to result from chronic or acute whole-body exposure to ionising radiation.
Although these fears are largely without foundation, there are real health hazards associated with the chemical residue of spent DU munitions on the battlefield. However, these hazards can be minimised through prudent avoidance and common sense.
Depleted uranium is the extremely hard, dense material that remains when uranium 235 is extracted from natural uranium. The U-235 is used as a fuel for nuclear fission reactions but the remnant DU is not capable of nuclear fission. Because of its hardness and density - and not because of its radioactivity - DU was first used in battle in the form of long-rod penetrators, which are heavy, elongated darts fired at hypersonic velocities from tank main guns to penetrate the armour of other tanks.
These projectiles achieved astonishing results in the Gulf War, proving themselves many times more effective than previous penetrators made from tungsten alloys. They punch through conventional rolled steel armour and modern layered composite armour with ease. DU has also been used to make armour-piercing bullets for the huge GAU-8 30 mm rotary cannon mounted on US-made A-10 tank-killing aircraft employed in Kosovo.
The hazards of handling intact DU rounds are minimal. It is only weakly radioactive. DU emits radiation in the form of alpha particles which are easily absorbed by air, paper, or skin: in this sense it is no more hazardous than the luminous paint used on the dials of old watches and clocks. When a DU penetrator or bullet travelling at high speed strikes armour plate, it does not explode but generates intense shock and heat. As it rips through the armour it tends to spall, that is to shed small dense pieces which scatter along the path of the projectile. These pieces of metallic uranium and glassy uranium dioxide dust are no more radioactive than the original projectile, but they are toxic when ingested and especially when inhaled.
Because of their density they tend not to blow in the wind nor to contaminate ground water, so the toxic hazard is confined to the immediate vicinity of the target, particularly the interior of the destroyed vehicle. DU projectiles which do not strike dense armour - a large fraction of the rounds fired from aircraft-mounted cannon in a typical engagement - remain intact and do not produce toxic dust.
The correct procedure is to seal and impound or bury affected vehicles, and those who must survey them should wear impermeable chemical protection suits and breathing apparatus, not radiation suits. If a person were unfortunate enough to inhale or ingest some of the uranium dust from a destroyed tank, and did not seek prompt medical intervention, the disease most likely to occur would be localised tumours of the lungs, digestive tract or other site of ingestion after several years, not leukaemia after a few months.
I understand that Irish troops have not been operating or moving in areas when DU projectiles have impacted. In this case, they should be quite safe, at least from DU dust contamination. May they all return safely and in good health! - Yours, etc.,
John McInerney, Professor of Physics, University College, Cork.