Aughinish Alumina Ltd last night welcomed the report. Mr Damien Clancy, plant manager, said in a statement: "The company and all its employees have waited a long time for this clean bill of health in environmental terms."
He added: "We have always maintained that Aughinish Alumina has not contributed in any way to them [the problems], and this has now been confirmed.
"It is very important to all of us here in Aughinish that our operation has been given a clean bill of health in this matter. Given the scale of the investigation and the detail in the report, the company wishes only at this time to welcome, in broad terms, its findings."
However, Green Party MEP Ms Patricia McKenna was critical of the report.
She said it "goes about denying every single problem that has taken place in Askeaton and offers no solution whatsoever to the dozens of mysterious deaths of farm animals and the chronic health problems experienced by local farmers and their families.
"This report is striking the last blow against farmers who have experienced enormous losses and psychological traumas over the past 10 years."
She called on the State "to have the decency to proceed now with an independent and indepth medical investigation of animal deaths and health problems continually experienced by local residents. The matter must not end there. It is essential that the truth about this be found and told.
"From the very start, the EPA has never been prepared to acknowledge that there were serious problems in Askeaton," she said.
"I think it is profoundly shocking to witness such a total collapse of public accountability and State-orchestrated denial of such great hardship and extraordinary events."
The ESB, which has two plants in the area, Moneypoint and Tarbert, said it welcomed the EPA report. "We have cooperated fully with this lengthy examination" and the company was "studying the conclusions of this report".
The ESB statement added: "We note that the conclusions as regards emissions in the area concur with ESB's own findings." Mr David Thompson, a national council member of the Irish Farmers' Association, said the report was "a waste of money, and a bit of a charade".
Mr Thompson, who is a farmer and an animal nutritionist, said the report found no reason for the animal health problems in the area.
But he said he was "extremely disappointed" with the insinuation that the finger of blame was pointed at the farm advisory service, veterinary practitioners and farmers.