The British Prime Minister, Mr Tony Blair, has told Sinn Fein he will look into concerns about Sellafield and cancer along the east coast of Ireland, a Sinn Fein negotiator has said.
The party's ardchomhairle member, Mr Arthur Morgan, part of the Sinn Fein negotiating party at Downing Street last week, said he had raised the issue.
Mr Morgan, a founder of the Cooley Environmental and Health Group, which wants Sellafield closed, said a study had indicated that Co Louth has a cancer rate of 14 per cent above the national average.
"After our negotiations with Tony Blair last week, Gerry Adams asked for the meeting to run on and he introduced the issue of Sellafield. I told Tony Blair I want him to close Sellafield."
He said Mr Blair then gave an undertaking that he would look into the concerns and get back in touch with him.
Mr Morgan added: "I am also calling on all political parties and environmental groups to come together and collectively call for the closure of the Sellafield complex. We need unity on this and if it is there, the governments will have to listen to us and act accordingly."