Dublin City Council could be facing a massive bill in compensation to residents of Ringsend, Sandymount and other areas affected by the stench from its "state-of-the art" sewage treatment plant on the Poolbeg peninsula.
Earlier this month, the Ringsend, Irishtown and Sandymount Environmental Group threatened to seek a High Court injunction to restrain the "nuisance" caused by the €300 million plant and to sue the council for damages and costs.
Barrister Colm Mac Eochaidh, who is legal adviser to the Sandymount Residents Association, said he believed such an action would succeed. "Certainly, foul odours constitute a nuisance that can be sued over, and the remedy is injunction or damages".
Although he conceded there was no basis in Irish law for a US-style "class action", Mr Mac Eochaidh said there was "no reason why 200 people couldn't be named as plaintiffs" in the action, opening up the possibility of substantial damages.
Causing a nuisance has been an offence under common law since medieval times, though a legal action might equally challenge whether the city council or Celtic Anglia, operators of the treatment plant, has "lawful authority" to emit foul odours.
The plant, which has a throughput of 500 million litres of waste water a day, was developed under a "design, build and operate" contract by a consortium involving Ascon, sewage specialists Black & Veatch and Celtic Anglia, a subsidiary of Anglia Water.
Standards for the plant's operation were laid down in the environmental impact statement (EIS) on the project and covered effluent levels, sludge disposal and odour emissions, which were set at 100 parts per billion at its perimeter fence.
Since it started operating in July 2003, local residents have complained about foul odours emanating from the plant. The Ringsend, Irishtown and Sandymount Environmental Group has written to the city council on numerous occasions about the smell.
The council has already invested €1 million in "odour-abatement measures" and stepped up monitoring throughout the area. Earlier this year, it also commissioned US consultants CDM to examine the problem and suggest how it might be resolved.
Dublin city engineer Michael Phillips said the issues raised by CDM were "fairly complex" and copies of its draft report had been circulated to Celtic Anglia and its partners for comment, with a view to devising a plan of action next month.
Mr Phillips conceded that there "could be a number of legal issues arising" from the report, but he said the consortium had pledged to "work with us to resolve the problem and, at some date in the future, we will discuss whose responsibility it is".
A spokesman for Celtic Anglia said it had no comment on the pending legal action, other than to say that the company had not been served with proceedings. "It appears the residents are taking issue with the city council rather than us," the spokesman said.
Last April, the European Commission said that it was taking legal action against the Government for its failure to address a number of environmental issues relating to the Poolbeg sewage treatment plant, including the odour problem.
The commission's action is in response to an official complaint from Green Party chairman John Gormley TD, who represents Dublin South East. Ironically, the European Union provided a substantial part of the funding for this "flagship project" under the National Development Plan.