Their claims have been investigated by Wiltshire police who say they now have enough evidence to charge up to five retired scientists with criminal offences.
Soldiers were exposed to the deadly nerve gas sarin during experiments at Porton Down, a chemical and biological defence establishment on Salisbury Plain in Wiltshire, between the 1950s and 1980s.
The Ministry of Defence (MoD) tests carried out on several Cornish servicemen could now lead to prosecutions.
Veterans say the chemical tests left them with long-term ill health.
Their claims have been investigated by Wiltshire police who say they now have enough evidence to charge up to five retired scientists with criminal offences.
In an unprecedented move, the force will ask the Director of Public Prosecutions to take the scientists to court for allegedly duping the volunteers into taking part in the tests.
The Ministry of Defence's chemical and biological weapons research centre has tested 3,000 service personnel in human volunteer experiments since 1945.
More than 300 ex-servicemen claim to have suffered disabilities ranging from breathing difficulties to kidney complaints as a result of tests carried out at the centre run by the Defence Evaluation and Research Agency (Dera).
Nerve agent
It was revealed earlier this year that a coroner had applied to hold a fresh inquest into the death of an airman who took part in one of the experiments.
It is claimed that 20-year-old Mr Maddison died after 200mg of the deadly nerve agent sarin was dripped on to a patch of uniform taped to his arm at Porton Down.
The original inquest into his death was held 48 years ago behind closed doors, where a coroner concluded he died of asphyxia.
The coroner's report was never released and the only relative allowed into the inquest was the airman's father, who was sworn to silence under the Official Secrets Act.