The Environmental Protection Agency (EPA) has announced that it intends to refuse a waste licence for a proposed £16 million superdump in a disused open-cast mine at Silvermines, Co Tipperary.
In its first outright refusal of a landfill licence, the EPA said it was not satisfied "that pollution of groundwater will be prevented".
Waste Management Ireland (WMI), part of a US multinational and one of the world's biggest waste management companies, planned to bring waste from adjoining counties and to dump 450,000 tonnes of it annually for 25 years.
WMI's development manager, Mr Mark Gilligan, last night said the company was "disappointed with the decision" but would concentrate on the oral hearing next week.
The EPA gave eight reasons for its ruling. "Having regard to the risk of instability and substance, and the risk of failure to the liner system, the agency is not satisfied, on the basis of the application, that pollution of ground water will be prevented," it said. And it was "not satisfied that the facility can be constructed in accordance with details provided in the application".
It added: "The potential pollution of stream sediments by discharges to surface water has not been satisfactorily addressed."
The EPA also found that the development "does not address the potentially negative impact of the facility on the achievement of national prevention, minimisation and recycling targets set out by Government waste management policy".
Local residents and the Silvermines Environmental Action Group (SEAG) welcomed the announcement. Mr Eamon De Stafort, SEAG spokesman, said: "This is the removal of one of our biggest obstacles. We did not expect a decision from the EPA so soon. People here are jubilant. However, the battle is not over. But the proposed decision augurs well for the local community."
A local Labour Party senator and councillor, Ms Kathleen O'Meara, said that the decision was "very significant and welcome" because it set out comprehensively why the Silvermines site was "totally unsuitable".
Ms Marie Hoctor, a Fianna Fail councillor, said: "It is obvious from the proposed EPA decision that groundwater is threatened to the extreme. It is unlikely that the development would ensure that water quality would remain at acceptable EU standards."