The Environmental Protection Agency has estimated that as many as 170,000 homes, particularly in Munster and Connacht, are at risk from radon.
Radon is a radioactive gas which has been linked with an increase in lung cancer and has been described as “serious public health hazard” by EPA director Micheál Lehane.
Homeowners are now being urged to test their homes for the presence of radon.
Radon is a gas that has no taste, smell or colour and originates from the decay of uranium in rocks and soils.
It is a cancer-causing radioactive gas and the EPA has said that 350 cases of lung cancer in Ireland every year can be linked to radon.
In open air, radon is harmless, though in enclosed spaces like a house, levels may build up as the gas enters through cracks in the floor or gaps around pipes or cables.
Tiny radioactive particles are suspended in the air, and when inhaled, give a radiation dose that may damage lungs.
The risk of developing cancer is increased if you remain exposed to high radon levels in your home and is increased further for smokers.
This interactive map provided by the EPA shows areas across the country which are at increased risk of radon exposure.
According to the EPA, it shows “a prediction of the number of houses in any one area that are likely to have high radon levels”.
By entering your Eircode or address in the search bar, you can determine whether your home is in an at-risk area.
Areas in red are most at risk from radon and are called High Radon Areas, determined by analysis of indoor radon measurements as well as bedrock type, quaternary geology, soil permeability and aquifer type.
The areas of the map in orange and yellow are areas of medium and low risk respectively.
High traffic volumes to the online map have resulted in it crashing for some users, however an EPA spokesperson said: "We are working hard to get these up and running and will let you know once they are operating again".
The presence of radon can only be measured using special equipment, and the EPA has a list of registered radon testing services.
Testing for radon involves placing two small detection devices in the house for three months to allow for variations in levels due to weather and ventilation changes.
The detection devices are then posted back by you to the testing laboratory where radon levels are measured in becquerels per cubic metre, expressed as Bq/m3.
If radon levels read above the national reference level of 200 Bq/m3, the EPA recommends that you should consider taking action to reduce these levels.
Known as ‘radon remediation’, there are two ways to solve the issue: preventing radon from entering your home from the ground or removing radon from your home after it’s entered.
Re-testing is required after radon remediation to make sure levels are below national standards.
The cost of a test is €50. Remediation works can cost between €1,000 to €2,000 and support systems are expected to be put in place.
Eugene Monaghan, who operates a radon remediation company, told RTÉ radio that the good news was that if high levels of radon were detected in a home “it can be fixed” through the installation of a radon tracking fan. The fan draws radon from under the ground “and blows it off into the atmosphere.”