Ground combat in the 1991 Persian Gulf War lasted just 100 hours, but it's meant 17 years of pain and anguish for hundreds of thousands of veterans who went. Recently, though, many of the sufferers have been given a new reason to hope.

A congressionally-mandated panel has concluded that "Gulf War syndrome" is real and that more than a quarter of the 700,000 US veterans of the 1991 conflict suffer from the illness.

The most extensive-ever report on the debilitating, multi-symptom illness released Monday concluded that it is caused by exposure to toxic chemicals including pesticides, used against sand flies and other pests, and a drug administered to protect soldiers against nerve gas.

"The extensive body of scientific research now available consistently indicates that Gulf War illness is real, that it is the result of neurotoxic exposures during Gulf War deployment, and that few veterans have recovered or substantially improved with time," said the 450-page report, presented to Secretary of Veterans Affairs James Peake.

"Veterans of the 1990-1991 Gulf War had the distinction of serving their country in a military operation that was a tremendous success, achieved in short order. But many had the misfortune of developing lasting health consequences that were poorly understood and, for too long, denied or trivialized," the report said.

The report's producer, the Research Advisory Committee on Gulf War Veterans' Illnesses comprised of scientists and veterans, was chartered by Congress in part because of many complaints that veterans were not receiving adequate care.

The committee's scientific director, Boston University school of public health dean Roberta White, said the findings "clearly substantiate veterans' beliefs that their health problems are related to exposures experienced in the Gulf theatre."

She said veterans "have been plagued by ill health since their return 17 years ago. Although evidence for this health phenomenon is overwhelming, veterans repeatedly find that their complaints are met with cynicism and a 'blame the victim' mentality that attributes their health problems to mental illness or non-physical factors."

The report said Gulf War illness is typically characterized by memory and concentration problems, persistent headaches, unexplained fatigue and widespread pain, and may also include respiratory symptoms, digestive problems and skin rashes.

The panel cited two exposures causally associated with Gulf War illness: the drug pyridostigmine bromide, or PB, given to soldiers to protect against nerve gas; and pesticides widely used during the war.

The panel noted that federal funding for Gulf War research had dropped dramatically in recent years and urged 60 million dollars in annual funding.

Gulf War syndrome is the popular name for a chronic multisymptom illness complex first identified by the US Centers for Disease Control and Prevention in 1994 after thousands of returning troops complained of numerous unexplained symptoms.

Several earlier reports pointed to the stress of combat as a likely explanation for the illness.