A group from Wales is campaigning for the UK government to overturn a decision to stop compensating people suffering from an industrial illness.
Asbestos exposure can cause pleural plaques
People with the condition pleural plaque - a scarring of the lungs caused by asbestos, which can lead to cancer - were previously entitled to damages.
The House of Lords ruled it was not a disease in its own right last October.
The campaign, run by industrial solicitors and the GMB union, has organised an online petition.
The plaque areas can develop into a type of cancer called mesothelioma, a rare condition caused by inhalation of asbestos fibres or dust, as well as other asbestos-related diseases.
In Wales, 300 men and women are diagnosed with the cancer every year and thousands have pleural plaques.
The British Lung Foundation has organised an Action Mesothelioma Day on 27 February to raise awareness of the condition.
Following the Lords' ruling, the Scottish Government put forward a bill which will reverse the decision in Scotland, entitling Scottish workers affected by the condition to continue claiming industrial compensation.
Mark Church, partner at law firm Leo Base and Cohen which is leading the campaign, said pleural plaques were the "calling card" for mesothelioma and wants Welsh sufferers to have the same compensation rights as Scottish ones.
"Before this decision, not only could we successfully obtain damages on behalf of victims with pleural plaques, but we also had the reservation that if they got the horrible disease of mesothelioma, they could come back in the future to quickly get their compensation," he said.
"I have several clients who have pleural plaques and are living with the fear that it could develop into fatal conditions like mesothelioma.
"They deserve compensation for the extreme worry and anxiety of living with pleural plaques."
GMB Wales legal officer Nick Hughes said: "Pleural plaques are described by medical textbooks as a disease.
"The law has always accepted that scar tissue on the outside of the body is an injury so we believe that scar tissue on the inside of the body should be deemed the same."
John Hill, 71, from Swansea, worked as a thermal insulation engineer for 15 years working with asbestos at firms in Wales before masks were introduced in 1967.
He was able to make a claim before the ruling last year and secure damages, but said: "The disease that I contracted is something you get through exposure to asbestos so it's only fair that I got compensation.
"I think it's disgusting that people in my situation can't recover damages following the recent ruling.
"I have witnessed my two brothers both die of asbestosis and know first-hand that those suffering with pleural plaques are only going to get worse."