The Taoiseach insisted that there was advice available to those who had to carry out remedial work on their houses to deal with the problem of radon gas.
Mr Ahern said the issue was serious. "The radiological institute has done several surveys highlighting for people how they can, at minimum cost to themselves, take preventative measures to deal with the issue," he added. "That is what people should be doing."
It was not a question of having to rebuild a house, he added.
The Labour leader, Mr Pat Rabbitte, said that radon gas was "a secret, deadly killer". The cost involved in dealing with it was about €10,000 per unit. He added that 100,000 identified houses were at risk from radon gas.
He said last week's report from the Radiological Protection Institute (RPI) had shown, yet again, that 200 people die of lung cancer directly attributable to radon gas.
"That is more than half of the people who die in road accidents every year where we quite properly spend tens of millions in the effort to save lives," he added.
The counties in high risk areas were Carlow, Kilkenny, Waterford, Wexford, Wicklow, Clare, Galway, Mayo and Sligo, where "the chances of dying are one-in-50 from a lifetime of exposure to radon." This, he added, was twice the risk of a car accident.
Mr Ahern said: "I do not wish to be flippant. An issue is either serious or it is not. There are other concerns in this area and asbestos is probably a more serious issue than radon gas." He added that the RPI had done several surveys, and had pointed out that basic issues of ventilation in old houses would dramatically improve the situation.
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