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Radon in the Workplace

What is radon?

  • Radon is a natural radioactive gas. You cannot see, hear, feel or taste it. It comes from the minute amounts of uranium that occur naturally in all rocks, soils, brick and concrete.
  • Radon is present in the soil in all parts of the UK to varying degrees. Most of it seeps from the ground harmlessly into the atmosphere. However, where it enters buildings, levels can build up and occasionally become a significant radiation risk to people inside. The highest levels are usually found in underground spaces such as basements, caves and mines.
  • The Health Protection Agency and the British Geological have undertaken a survey of the UK to identify radon affected areas. An atlas of radon areas in England and Wales can be obtained from
  • Pembrokeshire is one of the areas in the UK which has generally higher levels of radon.

What are the effects of radon?

Most radon gas breathed in is immediately exhaled and presents little hazard, however the decay products of radon are radioactive which exposes employees to increased health risks. Radon is the second largest cause of lung cancer in the UK after smoking and so precautions may be needed if your staff work in a high radon environment. For more information visit:

What are the requirements of workplaces?

Unless you have already done so, health and safety legislation requires you to assess the radon risk in your workplace. Firstly you will need to establish whether your business premises are situated in a radon Affected Area. Within Pembrokeshire, almost the whole county is a designated Affected Area. Employers who only occupy the first floors of a building and above are unlikely to have a significant radon level, employers who use cellars, basements and poorly ventilated ground floor rooms are far more likely to have problems with high levels.

The Health Protection Agency advocates five essential steps to assist employers in meeting their obligation, these are as follows:

  • Measurement
    -take measurements wherever employees are employed in radon affected areas
  • Surveillance
    -ensure regular monitoring of levels, employees health and mitigation measures in place
  • Risk Assessment
    -carry out a risk assessment of the potential risk to employees and others that may enter the premises
  • Mitigation
     -necessary works to be completed within 6 months
  • Maintenance
     -regular maintenance to ensure control system is effective

How to I measure radon levels?

The only way to determine whether radon levels within your premises are high is to measure the concentrations in the air. Once this has been carried out a risk assessment would be undertaken to determine whether further action is needed. We expect less than 1 in 25 of our workplaces to require action to reduce radon levels, but where this is required, it is usually carried out using standard building techniques.

Radon levels measurements can be obtained using inexpensive dosemeters that you order online and receive through the post. You then site them in areas of your building - usually for 3 months. The Health Protection Agency website, contains up to date details of validated laboratories that supply such dosemeters, practical information on locating dosemeters and carrying remedial action can also be found at the Health and Safety Executive website,

On measuring, if the level shows radon levels below 400Bq/m³ then the only further action required is to decide when the risk assessment will be reviewed. In occupied workplaces where the level exceeds 400Bq/m³, the employer may need to take immediate steps to manage occupational exposures to reduce the radon levels. A specialist radon advisor would then be able to advise on the most appropriate remedial action.

What work is being carried out?

The Health and Safety Executive Strategy 2005-2010 outlines the need to focus on radon affected areas in order to reduce the high employee and public exposure levels to radiation. This will be done through the provision of information and advice, direct contact with employers and working with stakeholders. During October 2010 Officers from both Pembrokeshire County Council and Health and Safety Executive will be carrying out visits to businesses within Pembrokeshire to discuss this issue, check that measurements have been or are being carried out, and ensure employee exposures are as low as reasonably practicable. If you have carried out work in the past to measure radon levels and/or taken remedial action, you are reminded that this would need to be under regular review.

For further information contact:

Health and Safety Team,
Public Protection Division,
Pembrokeshire County Council,
County Hall,
SA61 1TP

Tel: 01437 775179

E-mail: health&

ID: 20757 Revised: 1/8/2016