Six members are suing the State, claiming their health was adversely affected due to working with hazardous chemicals.
An investigation by the Irish Examiner also revealed the Health and Safety Authority threatened to prosecute the Air Corps in 2016 unless it implemented improvements in the management of employees’ exposure to hazardous chemicals.
It found staff did not have access to basic equipment, such as gloves, goggles, and protective clothing.
Calling in the Dáil for separate investigations, Fianna Fáil leader Micheál Martin described the revelations and lack of response as a “serious scandal”.
He also accused Taoiseach Enda Kenny and the Government of trying to “bury” the controversy.
The Irish Examiner also revealed three whistleblowers had written to Mr Kenny and then defence minister Simon Coveney in 2015 and made a number of protected disclosures.
However, neither Mr Kenny nor Mr Coveney contacted the men.
Mr Martin said he had spoken to whistleblowers who feel the Government did “not accept anything they are saying”.
He called on the Taoiseach to establish an independent health study of aircraft maintenance personnel and a separate independent board of inquiry into the handling of what he described as “the entire affair and scandal”.
Mr Martin said it was “extraordinary” that there was no monitoring of employees’ health at Casement, as required by law, and that personal protective equipment was not provided to those working with hazardous chemicals.
“Isn’t it extraordinary that in 2016 the Health and Safety Authority is writing to our own Air Corps to say very basic provisions of our law should be implemented?” said Mr Martin.
He compared the situation to that in Australia, where air force maintenance staff were compensated for illnesses caused by exposure to harmful chemicals.
“The response of the State has been standard and deeply depressing. It has resorted to the courts. There are currently six cases before the courts, and the Government is fighting them very strongly and acknowledging no negligence,” he said.
“Why was the State so slow to respond to the whistleblowers and to investigate the health conditions at Baldonnel [Casement]? Why were the whistleblowers not acknowledged by the minister?” asked Mr Martin.
Mr Kenny said the matter is being reviewed by an independent third party, the second to be appointed to investigate the claims. He told the Dáil it is “quite difficult to get somebody with the range of competences to deal with all the implications of hazardous substances and that sort of area”.
However, the Irish Examiner has learned that despite being appointed last September, the investigator has not spoken to any of the whistleblowers.
Mr Martin said: “The Taoiseach has not explained what happened between 2015, when the protected disclosure was made, and why the minister, Deputy Coveney, did not acknowledge and respond to the whistleblowers. There is a sense that this has been buried.”