Radon gas in buildings

Radon is a naturally occurring radioactive gas that results from the decay of uranium in rocks and soils. The gas is colourless, odourless and tasteless and can only be measured using special equipment.

In the open air, radon is harmless. But in an enclosed space such as a house, it may build up to an unacceptably high level. Radon from the ground enters buildings mainly through cracks in floors or gaps around pipes or cables.

The Office of Radiological Protection is part of the Environmental Protection Agency (EPA). It is responsible for regulating, monitoring and advising on radiation matters. It assesses radon levels and identifies areas likely to be radon hotspots.

How is radon harmful?

Radon decays to form tiny radioactive particles, some of which stay suspended in the air. When you inhale these particles, they give a radiation dose that may damage your lungs.

Radon has been shown to be a cause of lung cancer. Remaining exposed to high levels of radon in an enclosed area can increase your risk of lung cancer, particularly if you smoke. You can find out more about the effect of radon on your health.

Homes in some parts of the country are more likely to have a radon problem than others. Use the EPA’s interactive radon map to check if you live in a high radon area. This is different to having your home tested for radon. Even if you are living in a low radon area on the map, your home may have high levels of radon when tested.

Every home has different amounts of radon so the EPA recommends that everyone has their home tested for radon. The EPA has a list of registered radon testing services.

Testing involves placing two small detection devices in the house for three months. This period allows for variations in radon levels due to changes in weather, ventilation, and so on. At the end of three months, you post the detectors back to the testing laboratory. The lab calculates the radon level in becquerels per cubic metre, expressed as Bq/m3. Read more about testing your home for radon.

If the radon level in your home is over the national reference level of 200 Bq/m3, the EPA recommends taking action to reduce the level of radon in your home. This is called ‘radon remediation’.

The two main methods of radon remediation are to:

• Prevent radon entering your home from the ground underneath
• Remove the radon after it has entered your home

In either case, you should have your home re-tested after the work has been completed to ensure the radon level has dropped below 200 Bq/m3.

Radon remediation works may qualify for the Home Renovation Incentive scheme.

If your workplace is located in a high radon area on the EPA’s interactive radon workplace map, your employer must test the workplace for radon. You can read more about radon testing in the workplace on the EPA’s website.

The Department of Education arranges radon tests for schools. You can read more about radon testing in schools and find out how to check the radon levels of your school on the EPA's website.

• For information about radon and how you can reduce your exposure to radon levels in your home, see the EPA’s webpage on Radon for Householders
• Read more about radon in the World Health Organisation’s factsheet
• Find out about the National Radon Control Strategy