Has the updated radon potential map affected your risk assessment?

Vicki Filby-Filson
Senior Consultant, Assurity Consulting
20th March 2023

In December the UK Health Security Agency (UKHSA) and the British Geological Survey (BGS) published an updated radon potential map for Great Britain. This is the first update for more than 10 years and provides an authoritative analysis of the likelihood of a building being in a radon Affected Area (an area with higher radon potential).

What is radon?

Radon is a colourless and odourless gas that exists in all rocks and soils, however, geology dictates where it is more likely to be present in buildings. Think back to the periodic table – it is an element and sits down on the right. Radon is attributed to 1,100 lung cancer deaths per year in the UK and the risk is higher for smokers and ex-smokers, however for most people the risk is low. UKHSA state that levels of radon have not increased, however, the map update is from new analysis and research including a large database of in-home measurements.

What do you have to do?

If your property is in a radon Affected Area, you should arrange for testing. The HSE has set the following criteria for risk assessments:

  • Above-ground workplaces should include a measurement in ground-floor rooms if the building is in a radon Affected Area.
  • Risk assessments in below-ground occupied areas should include a measurement regardless of location on the map

What is an occupied area?

The HSE defines this as a workplace occupied more than an average of an hour per week or 50 hours per year.

How do you test for radon?

Inexpensive surveys can be carried out by leaving small plastic passive detectors in rooms or occupied locations of interest. Public Health England has details of suitable laboratories and these usually post the devices which you then send back to them for analysis.

Steps to take 

  • Check where your property is on the UK radon map
  • Carry out a risk assessment considering radon potential, occupancy, and use of any below-ground areas
  • Where indicated in HSE guidance, arrange a measurement
  • Take steps based on the results

Anything else?

The HSE recommend that you encourage employees to test their homes if they live in a radon Affected Area.

Further information can be found at 

Radon in the workplace (hse.gov.uk)

UKradon - UK maps of radon