Until now, successive governments have refused to acknowledge the existence of multiple chemical sensitivity (MCS), caused by chemical poisoning, which experts claim is experienced by as many as one person in 10.
Sufferers develop allergic reactions after being exposed to products including pesticides and wood treatments.
The chemicals can cause blackouts, memory loss and vomiting when those affected subsequently come into contact with ordinary domestic products, such as hairsprays or washing powder.
Several studies have dismissed the disorder as psychological and have linked it with child abuse. But a report commissioned by the Health and Safety Executive has concluded that the illness does exist and could be caused by chemicals affecting part of the brain.
The study, carried out by the Institute of Occupational Medicine and endorsed by the Department of Health, also links MCS with other unexplained 20th-century illnesses, such as chronic fatigue syndrome and ME.
Campaigners say victims now plan to sue companies including Monsanto and Zeneca, which they blame for not giving adequate warning of possible side-effects from the toxic chemicals they use to produce pesticides and insecticides.
They believe that manufacturers should be forced to seek safer alternatives to substances such as lindane, which has been blamed for many cases of MCS.
Margaret Anderson, a victim, says lindane is responsible for ruining her life. The retired civil servant has suffered from an irregular heartbeat and muscle spasms since her neighbours in Ludlow, Shropshire, had their house treated with the chemical nearly eight years ago.
Miss Anderson now suffers an allergic reaction if she drinks coffee or smells diesel fumes. "When they treated the house I was gasping and choking and my doctor referred me to the Birmingham Poisons Unit.
"Then I found out that I reacted if I had a glass of wine or touched washing powder," she said. "My social life has been reduced by half and I have to avoid hospitals like the plague because of the chemicals that they use.
"Doctors are not trained to deal with this and most women just get shunted on to hormone replacement therapy. This report is a step forward because it recognises there is a problem for the first time."
Felicity Mankin trained as a botanical ecologist. She has not redecorated her house for 15 years and can black-out just carrying out everyday chores like going to a supermarket.
Her problems began as a teenager, when she was exposed to lindane in woodworm treatment.
"I used to be very active and sporty but it got so bad that I would black- out just watching television," she said.
"I got a job with the gas board which was above an old petrol station and had gas heaters. I kept blacking-out and no one knew why.
"Now my carpets are worn into holes because I dare not have them replaced, and I have to pin my Reader's Digest to my lawnmower outside until the chemicals used in the printing have faded."
Alan Care, a solicitor with the firm Russell Jones and Walker, has spent 10 years investigating pesticide cases. He says claims could run into millions of pounds, now that the disorder has official recognition.
"Victims have been treated like canaries down mines. This is an important step because it strengthens the battle for compensation," he said. "There have been cases in the past which have failed because judges have dismissed the existence of MCS. This removes all the doubts."
Professor Jonathan Brostoff, director of the centre for allergy research at University College London, says the condition has already been recognised in America.
"This plays so much havoc with people's lives," he said. "A lot of chemicals can affect them, even formalin in chipboard cupboards.
"It has already been recognised in the States and it is good news that it has at last been recognised over here. This means patients now have an official document on their side."
Alan Dalton, a member of the Environment Agency board and an independent health and safety consultant, said chemical companies should be forced to find safer alternatives.
"This was recognised in the US years ago, but has taken a long time here," he said. "So many people have had their lives ruined.
"Twenty-five years ago they said society would collapse if they got rid of asbestos, but it hasn't."Reuse content