Can radon gas cause cancer?

  • Radon is a natural radioactive gas. When radon builds up indoors to high levels, it increases the risk of lung cancer.
  • But levels of indoor radon in most UK homes are low, so the risk of developing lung cancer from exposure to indoor radon is low.
  • Most radon-related lung cancers could be prevented by not smoking.

What is radon gas?

Radon is a radioactive gas that comes from rocks and soil. It’s found naturally in the air outdoors at low levels, but can build up to higher levels indoors in some buildings.   

Radon gives out radiation. When we breathe radon in, the radiation can cause changes to the cells in our lungs, which can lead to cancer.


Can radon cause lung cancer?

Exposure to high levels of radon increases the risk of lung cancer. But only a small percentage (5%) of lung cancers in the UK are linked to radon - that’s 1 in 20 cases of lung cancer.

Most cases of radon-related lung cancer could be prevented by not smoking.

This is because lung cancers that are linked to radon are most likely to be caused by the combination of smoking and radon.


Find out how to stop smoking


What are the levels of radon in the UK?

Radon levels naturally vary in different parts of the UK, due to different types of ground. Indoor radon levels also differ between neighbouring homes and buildings.  

Most homes in the UK have low levels of indoor radon, and so the risk of developing lung cancer from radon exposure in the home is low. But some buildings may have higher levels of indoor radon.

You can use the website UKRadon to check the radon levels for a UK postcode. It has information on how to measure indoor radon levels in your home and also how to reduce high levels. You can also contact your local authority if you need advice.


International Agency for Research on Cancer (IARC). A review of human carcinogens: Radiation. Vol 100D (2012).

Darby, S. et al. Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies. BMJ 330, 223 (2005)

Brown, K. F. et al. The fraction of cancer attributable to known risk factors in England, Wales, Scotland, Northern Ireland, and the UK overall in 2015. Br. J. Cancer. 118, 1130-1141 (2018)

UK Health Security Agency. Everything you need to know about radon. Available at (Accessed: 22 March 2024)

Last reviewed: 26 March 2024

Next review due: 26 March 2027

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