The occupants of a house in Tralee that had unacceptably high radon levels were being exposed to the same amount of radiation as if they had undergone 18 chest x-rays per day, or 6,500 per year.

These startling figures were released by the Radiological Protection Institute of Ireland (RPII).

Radon, a naturally occurring radioactive gas present in all rocks and soils, is classified as a class A carcinogen by the International Agency for Research on Cancer. When it surfaces in the open air, it is quickly diluted to harmless concentrations. However, when it enters an enclosed space, such as a house, it can sometimes build up to high concentrations, leading to an 'unacceptable health risk'.

After smoking, long-term exposure to radon gas in the home is the greatest single cause of lung cancer in Ireland. The gas is linked to around 200 cancer deaths here every year.

According to RPII chief executive, Dr Ann McGarry, Ireland continues to have a ‘significant' radon problem, ‘with some of the highest radon levels found in Europe'.

"Our research indicates that there are over 91,000 homes with high levels of radon and just over 7,900 have been found to date. Exposure to high radon levels causes lung cancer and many families are unknowingly living with a high risk to their health. The fact is that every second day someone dies from radon-induced lung cancer," she explained.

The latest figures from the RPII show that over the last 18 months, 434 homes were identified as having high radon levels. The highest level was found in a house in Tralee, which had levels 26 times higher than acceptable.

"The occupants were receiving the equivalent radiation dose of approximately 18 chest x-rays per day or 6,500 per year," the RPII noted.

Meanwhile, 10 other homes in Kerry, three in Galway and one each in Wexford and Clare had radon levels 10 times above acceptable levels. The people living in these houses received the same amount of radiation as they would have received from 2,500 chest x-rays per year.

A further 39 homes had radon levels that were between four and 10 times higher than acceptable levels, while the remaining 384 had radon levels up to four times higher than acceptable levels.

The RPII pointed out that in the last 18 months, over 3,000 homeowners carried out a radon test in their home. It encouraged anyone who is living in a high radon area to follow suit.

Measuring radon and rectifying the problem are both ‘easy to do', the institute said.

In order to test for radon, one detector should be placed in a bedroom and a second detector should be placed in a living room for a three-month period. These detectors are available from the RPII and a number of private companies. They are sent and returned by post for analysis. Nobody needs to come to your home.

The cost of a measurement by the RPII is around €50.

If a moderate radon level is found, improving your home's indoor ventilation may cut this by up to half. The cost of this is low. If higher levels are found, installation of a fan assisted sump is the most common method of remediation. This can reduce radon levels by over 90%.

The sump can be installed in one day by a contractor, with little disruption to the home. The typical cost of this work is around €850, with annual running costs of around €100 depending on the size of fan installed.

An interactive map is available on the RPII website here to allow you to see if you are in a high radon area. Alternatively, more information is available on 1800 300 600.