MEN in white coats, backroom boys, faceless boffins, the scientists behind every fighting army, have been inventing killing machines for generations with devastating effect.

Clinically, scientifically, brutally churning out their wares, divorced from the reality they rain down on ordinary men. Acting without malice, they claim to mean no harm, living in a hypothetical world of "what ifs". They work to protect their side, not out of aggression for the enemy. They act in self-defence, to give their side the chance to strike first, to strike hard, to head off any possibility of a counter-attack.

Since the First World War they have been supremely good at ending human life and weapons today are deadlier than ever before.

They have also been supremely bad at considering the consequences, leaving the world with an apocalyptic legacy.

The depleted uranium shell, so effective at slicing through enemy armour, is falling from grace, the latest in a line of less-than-safe weapons.

But the problem started decades back at the beginning of the last century. "The first one must have been the use of poisonous gas during the First World War," says military expert and senior lecturer in modern languages, at Northumbria University, Dr Nigel Thomas. "It was the first time someone invented a weapon that did more harm to their own side than good." When the German boffins let loose mustard gas on British troops at the Front, it burned, it maimed and it killed.

But they hadn't accounted for a change in the wind which blew the deadly cloud back over their own lines, causing mayhem in the ranks. Since then, poison gas has been outlawed, never to be used again - though there are reports of Saddam Hussein using it during the Gulf War and against the Kurds. As a weapon against mankind it is effective, as a tactical tool it's not.

The Second World War pitted conventional arms against conventional arms, bullets, bombs and shells hurled with incredible ferocity. The poison gases were used in confined quarters on a persecuted race of civilians, not troops.

But the war was brought to an end by the men in white coats, scientists who unleashed on the world a weapon of untold madness - the atomic bomb.

The only two atomic devices ever to be used killed millions of civilians in Japan. Those who survived the initial blast perished later from the hideous effects of radiation. It changed the world and, for the first time, put it under the threat of total annihilation. And, like the indiscriminate gas, the nuke has been put away because it is also too dangerous to use.

Some of the other deadly sins in the "NBC" (nuclear, biological and chemical) armoury are the biological plagues which still sit in deep vaults in Siberia and Atlanta, a sinister by-product of the American-Soviet Cold War. But both sides know that, once released, the viruses can not be controlled, their effect even more arbitrary than gas.

And chemical agents now sit in the same vault in case the worst does come to the worst. They are there to be used by desperate leaders or madmen. Agent Orange was sprayed on an unsuspecting population with reckless abandon over the Vietnamese in the 1970s. The chemical was designed to defoliate trees which were providing the Vietcong such effective cover. The fact the Vietnamese fighters moved deep underground made no difference to the US generals.

All the Agent did was cause birth defects in the population for years to come.

"The NBC weapons are not terribly effective because they are actually too dangerous for either side to use," says Dr Thomas. "America's attitude has always been to spend lots of money on weapons in order to save lives. They spend millions on them and use so many it becomes an overkill. They have reached the point now where they have so many they could wage war without losing a single life. They just blaze away.

"Depleted uranium shells are just part of this same story. They are low grade nuclear weapons and the military says the dosage is so weak it doesn't matter. But it is now looking like they have underestimated them. I can foresee DU shells no longer being used because they are too dangerous for our troops."

While the scientists, ministers and generals bicker about whether the shells can cause cancer, a North-East family has reason to think they can.

David Robertson, 41, from Durham City, developed an illness after serving in the Gulf. He bleeds both externally and internally and has regular seizures - all conditions which could be caused by DU. He also suffers from epilepsy and is too ill to talk. But his mother, Georgina Hilland, says the issue is "another case of the Government trying to look as if it is doing something" when in fact it isn't. She is demanding a full inquiry.

Sunderland University professor and member of the Gulf War illnesses parliamentary group, Malcolm Hooper, also believes there is a risk from the shells - in wartime to the troops and in peacetime to anyone who lives near the factories which make them.

"Often these are covert and are not known to the local population," he says. He also claims there's a risk to anyone living near firing ranges where they are tested, even if they are miles away. "Because the dust can travel between 25 and 30 miles, it can get outside remote areas," he says.

The Ministry of Defence insists that the test-firing of DU shells, which has taken place over the past ten years at Eskmeals in Cumbria and the Solway Firth, doesn't pose a "significant risk" to the public or the environment.

Prof Hooper, who has given evidence on depleted uranium to the Defence Select Committee, adds: "I don't want to scaremonger but I think there is a very real risk. It's unquantifiable at the moment and, if I lived in such an area where there was production or firing, I would be very worried."

So the pressure is growing on the men in white coats to find an answer to the problem they created. In an ironic twist, it is no longer enough to invent effective weapons of destruction, they have to make sure they are safe as well.