It is claimed that lung cancer caused by radon gas in Irish homes is killing one person every two days.
The Radiological Protection Institute says one in 14 homes around the country has high levels of the substance which puts residents at an increased risk of getting cancer.
The naturally occurring gas develops when uranium in the ground decays.
However experts say radon is only a problem if its ignored and is urging people to get their homes tested.
Parts of Waterford, Kerry, Galway, Sligo, South Tipperary and Carlow have all been shown to have high levels of the gas.