Gulf War Syndrome was not caused by depleted uranium munitions, according to a new study.
Scientists from the University of Portsmouth tested Gulf War syndrome sufferers to examine levels of residual depleted uranium in their bodies.
They say their study "conclusively proves" that none of them were exposed to any significant amounts of depleted uranium during the conflict.
Professor Randall Parrish said: "For decades, medics and scientists have been looking for the elusive cause of Gulf War illness.
"That depleted uranium is not and never was in the bodies of those who are ill at sufficient quantities to cause disease will surprise many, including sufferers who have, for 30 years, suspected depleted uranium may have contributed to their illness."
WATCH: Professor Randall Parrish speaks about the study.
The study tested 154 well-monitored American Gulf War veterans who have the illness and not a single trace of depleted uranium was found in any of the samples following testing.
And Prof Parrish said "being able to debunk the alleged connection between this illness and this radioactive substance" allows a cleared focus on "what the likely cause(s) actually are".
"The plausibility of the link between depleted uranium and the illness has bubbled along now for nearly 30 years, but we would argue it's time to look elsewhere," he said.
Prof Parrish added the most likely remaining causes for the illness are low-level and widespread exposure to sarin nerve agent – widely released when troops destroyed caches of Iraqi chemical weapons.
He added this was possibly compounded by the use of organophosphate anti-nerve agent medication and the liberal use of pesticides to prevent malaria exposure to allied forces.
"The allies' own activities destroying an Iraqi nerve agent cache or spraying pesticides liberally on troops could be seen in hindsight as an inadvertent 'own goal' and one to be avoided in future conflicts," he said.
"It is important to find causes for conditions like this, even if it takes a long time and the causes might be controversial."
Gulf War Syndrome has been suffered by thousands of personnel from the military of UK, US and other allied nations.
It has caused a range of both acute and chronic symptoms including fatigue, headaches, joint pain, indigestion, insomnia, dizziness, respiratory disorders and memory problems.
Scientists believe it appears rooted in neurological impairment.
The Royal British Legion said its research suggests up to 33,000 UK Gulf War veterans could be living with the syndrome.
Andy Pike, head of policy and research at the Royal British Legion, said there has been "little meaningful research" about treating the illness in the UK.
"It is likely this lack of understanding has had a serious impact, leaving many veterans living with debilitating conditions 30 years after the end of combat operations."
Cover image: British troops move through the desert on Operation Granby in the first Gulf War (Picture: MOD).