Householders have been urged to test for radon after a house in Co Tipperary was found to have 45 times the acceptable level of the cancer-causing gas.
The Radiological Protection Institute of Ireland (RPII) said an estimated 91,000 homes in Ireland had high levels of radon gas and that only about 4,000 had been identified.
Very high levels of radon gas were detected in a house near Ballyporeen, Co Tipperary. The home had a peak reading in one room of 9,000 becquerels per cubic metre which is 45 times the acceptable level of 200.
The Tipperary householder tested the home for radon gas and immediately installed a radon sump.
Labour senator Phil Prendergast said it was "about time the Government took this health threat seriously" as it causes up to 10 per cent of all lung cancers in the State. She called for a grants scheme to allow those most at risk to radon-proof their homes.
The RPII is concerned that other homes in Ireland, and in particular this area, could have similar problems.
Radon is a naturally occurring radioactive gas that has no smell, colour or taste.
Testing for the gas involves putting a radon detector in a bedroom and a second in a living room for a three-month period.
