The Green Party's complaint in relation to the proposed new prison and central mental hospital site at Thorntown, Kilsallaghan, Co Dublin is to be investigated by the EU environment commissioner.
The construction of the prison is exempt from an environmental impact survey as it is deemed to be in the interests of national security.
The Greens complained to Commissioner Stavros Dimas that this is a deficiency in Irish legislation. "Minister McDowell has entered into a contract for almost €30 million without carrying out a environmental impact study," said Green Cllr Joe Corr.
Cllr Corr and party leader Trevor Sergeant made the complaint two months ago and received confirmation it was to be investigated by letter a couple of days ago.
"We are hopeful that they will come back and say Ireland is in breach of EU regulations and compel the Irish government to carry out an environmental study," Cllr Corr said.