Galway Bay fm newsroom - Large parts of the country - and in particular homes in the West - have been found to be at increased risk from radon.
New radon maps, launched by the Environmental Protection Agency, show an increased risk from radon in Ireland, with 170,000 homes now predicted to be at risk of radon exposure above the national reference level.
This is an increase of 45,000 homes, from the previous estimate in 2002.
The gas is naturally occurring, particularly in rock in western counties, and is linked to 350 new lung cancer cases in Ireland each year.
Senior scientist with the EPA, David Fenton, says it's a significant public health risk and people need to act.