We've known for over 20 years that there are risks. But we don't think those risks are significant. The 1990 warning came from the US-based Science Applications International Corporation. There have been other warnings. DU has been blamed for a number of leukaemia cases among former peacekeepers who served in the Balkans.
Veterans also say it contributed to health problems suffered after the Gulf War.
Little risk' DU is a heavy metal, 1.7 times as dense as lead. This makes it a potent weapon for punching through armour, and it is used mainly for attacking tanks and other armoured targets. The MoD, the Pentagon and Nato maintain that it poses little risk on the battlefield or subsequently, though they do say that troops entering vehicles struck by DU munitions should wear protective clothing. They argue that the main danger from DU comes from its chemical composition, not from its radioactivity. But it is hard to see how any of them could claim not to have known of the wider risks before the start of the Gulf War.