Radon Gas - The Facts

Are you aware of your responsibilities as a landowner using or letting property where there may be radon gas?   


It is a radioactive gas that generally emanates from uranium. 

There are 2 sets of circumstances where radon gas can occur. 

1. Naturally Occurring Radon Gas 

This is in rocks and soil and is normally an issue when buying properties in Cornwall, parts of Devon, Wiltshire, Somerset, Avon, Shropshire, Wales, the North West and the East Midlands. 

The concern is generally that radon gas can collect and if not vented out of a property a build-up can cause health problems.  

With older properties which tend not to have double-glazing and suffer from drafts this is less of an issue because were any radon gas to be seeping into a property it tends to vent itself naturally. 

2. Other Radon Gas

Radon Gas is a by-product of the decay of uranium and thorium and may be found in buildings where they have been used or stored. 


1. Employers 

Under the Health and Safety at work legislation employers are, as far as reasonably practicable, required to ensure the Health and Safety of employees and other people who have access to their work environment.  A suitable and sufficient risk assessment must be undertaken.  Radon gas should be identified as a hazard if within the workplace where:- 

a) The building is in a radon affected area

b) A basement area is occupied for more than 50 hours each year

c) It is a mine, cave or other underground environment

d) There is a suspected radon source.

Where any of the above applies, testing is then required and the level of radon found informs the action that then must be taken.

2. Commercial Landlords 

Radon gas should be checked as part of a property's risk assessment. 

3. Residential Landlords

Under residential legislation landlords have a separate duty of care and obligations under the Housing Act to provide a safe home and should check for radon gas. 

4. Developers 

If one is building a new building or undertaking alterations in a radon affected area, then for building regulations purposes there might be a requirement  for testing and the installation of radon protective measures.  Such measures include venting radon gas outside the building. 

Radon Testing 

If you wish to test for radon gas within your property then an application should be made to Public Health England for a test kit for which they charge a fee that includes the cost of analysing the results after 3 months of testing. Where properties are determined to be above action levels then remedial works to improve ventilation should be undertaken. 

For further information please contact Joanna Damerell, Partner and Head of the Commercial Development team, at joanna.damerell@michelmores.com.