The GAA is not ruling out a legal challenge to An Bord Pleanala's unexpected decision to refuse planning permission for the retention of Croke Park's Hill 16 as a terrace.
In the most serious setback yet to the GAA's £140 million redevelopment of its flagship stadium, the appeals board said it was "not satisfied" that Hill 16 would "not endanger the health and safety" of supporters.
It said the decision was taken in the light of "the trend internationally, since the Hillsborough disaster of 1989, towards the provision of all-seater stadia" and the Department of Education's 1996 Code of Practice for Safety at Sports Grounds.
The board also said that, under the planning permission which it granted in 1993 for the redevelopment of Croke Park, it was to be an all-seater stadium with a capacity of 79,500. Retaining Hill 16 would mean increasing this to 84,000, with 10,500 standing.
Mr Danny Lynch, the GAA's spokesman, said the association was "extremely disappointed and surprised" by An Bord Pleanala's decision.
"We will be sitting down with our advisers to discuss the implications. At this stage no option can be ruled out."
He said one of the options would be to seek a judicial review of the board's ruling in the High Court.
"What this planning refusal means, in effect, is we will either have to cease using Hill 16 or seat the hill prior to going ahead with the Hogan Stand.
"One of the primary reasons we are spending £140 million on Croke Park is to provide enhanced safety and comfort. We also believe that our application to retain Hill 16 as a terraced area would have met any international standard and forensic examination for safety."
He noted that "The Hill", as it is often known, was built up using rubble from O'Connell Street after the 1916 Rising. It had also been "totally refurbished and rebuilt as recently as 1988". He rejected "any analogy with Hillsborough".
Mr Lynch said the GAA's view that Hill 16 was safe was shared by Dublin Corporation, which granted planning permission for its retention, and by "all the official voices of the local communities, which include five residents' associations, and their public representatives".
He said the appeal to An Bord Pleanala had been made by "a tiny handful of people who represent no one except themselves".
The board's ruling was "a sad day for Dublin followers in particular and for followers generally".
Mr Lynch disputed the board's contention that all-seater stadiums were the international trend.
"This applies more to Britain than to Europe, where they still have terraces - often up in `the gods', so to speak. Terracing is a fact of life in most stadiums."
Meanwhile, construction work on a new stand at the Canal End of Croke Park has been brought to a virtual standstill by the scaffolders' strike. Two decks of the stand were to have been ready for this year's all-Ireland finals but the GAA admits this is now unlikely.
As part of the application to retain Hill 16, the GAA had also sought planning permission to reschedule the phasing of the Croke Park redevelopment by combining the Canal End with the Hogan Stand. This has also been thrown awry by An Bord Pleanala's decision.