An Bord Pleanála only accepted one of its inspector's three reasons for rejecting the application to build the Corrib gas terminal at Bellanaboy in north Mayo.
The board decided unanimously to reject the application - solely because of the high risks posed by peat transferred from the terminal site and overlaid on neighbouring blanket bog.
The board feared that the overlay of peat at two metres deep across 94 acres of blanket bog would be unstable, especially as it was to be placed on a sloping site above the R314 regional road.
This would "constitute an unacceptable risk to the health and safety of the local community and of the general public on the public road in the vicinity of the site", it said.
It would also "constitute an unacceptable risk of pollution of salmonid waters in Glenamoy river, Sruwaddacon Bay and Carrowmore Lake and would seriously injure the amenities of property in the vicinity", it said in a decision signed by Mr Brian Hunt on April 29th.
The board's inspector, Mr Kevin Moore, gave three main reasons for rejecting the terminal in a 169-page report.
He cited visual obtrusiveness and adverse environmental impact; instability of the blanket bog to which excavated peat from the site is transferred; and the risk to human health under the Seveso II directive, given the proximity of the site to houses.
The inspector pointed out that projects similar to the Corrib proposal in other parts of the world were tied back to offshore processing platforms, and not to land-based terminals.
Where terminals were sited on land, they were in coastal areas and not inland in remote rural locations.
The developer had not proved that an alternative option was non-viable, the inspector said.
He also found that it would be "contrary to the strategic planning of infrastructural development for the Border, Midlands and Western (BMW) region" and would contravene the Mayo County Development Plan.
Defending its decision not to accept the first and third of the inspector's recommendations, the board said the visual impact argument would not warrant a refusal, given the "strategic nature" of the Corrib gas field development.
The board said that policy at a national level on provision of gas infrastructure was a matter for the Department of Communications, Marine and Natural Resources.
It also argued the proposed development would not necessarily be incompatible with the goals of the Mayo County Development Plan and the strategies for the BMW region.
The board did not accept the inspector's reason for refusal on health and safety grounds because the National Authority for Occupational Safety and Health did not recommend against the granting of planning permission, subject to a number of conditions.