All employers must consider the dangers of radon gas in their workplace. In essence this means identifying and assessing the risks of radon to employees, and taking action where the risk is identified as high due to potential exposure levels. The forthcoming publication of the Ionising Radiations Regulations 2017 means employers will have to comply with a new lower radon exposure limit.

Understand Radon and How It Causes Harm
Radon is a naturally occurring radioactive gas which comes from the ground. In some parts of the UK radon levels are higher than others, and it can build up in indoor workplaces, particularly in ground floors and basements. Radon becomes dangerous when its decay products attach to atmospheric dust and water droplets which can then be breathed in and become lodged in the lungs and airways. Some decay products emit hazardous alpha particles which cause significant damage to the sensitive cells in the lungs.

Radon is now recognised to be the second largest cause of lung cancer in the UK after smoking. Add to this the facts that lung cancer is the biggest cause of cancer-related death in the UK and that only 5% of lung cancers are curable, and you begin to understand why radon exposure must be managed.

The 3 Legal Requirements:
1. Assess: There is a duty to ensure the health and safety of employees and others who have access to their work environment under the HSW Act 1974. The Management of Health and Safety at Work Regulations 1999 require the assessment of health and safety risks and this can include radon.
2. Measure: If radon is an identified hazard, then you must find out what the radon levels are by measuring them.
3. Act: From 2018 you must act if radon levels exceed the workplace threshold in Ionising Radiations Regulations 2017. The combination of the radon level, occupancy time and workplace type will determine what action is required.

4 Key Steps to Identify and Manage Radon Risk:
Step 1 – Assess the Risk
Radon could affect any workplace or industry sector. You must assess the risk if you have a workplace which is below ground level, such as a basement, and is occupied for over an hour a week, or if you have workplace buildings in a radon ‘Affected Area’.
How to find out if you have a building in a radon ‘Affected Area’:
 If the building is less than 25 metres in length you can order a radon address search from Public Health England (PHE) for a small fee at:
 If the building is more than 25 metres in length you can order a report from the British Geological Survey, currently costing around £44, at:

If you do not have a workplace in an Affected Area, or a below ground workplace, you need to take no further action other than consider a review (see Step 4). If your workplace is in an Affected Area, or you have a below-ground workplace, proceed to Step 2.

Step 2 – Complete a Radon Survey

The only way to find out if a building is above or below the 2018 Action Level of 300Bq/M3 is to complete a radon survey. This process will usually need to be done via either PHE or a specialist contractor. It involves locating small plastic passive detectors in rooms of interest, usually for a 3-month period. The detectors are then removed and sent for analysis, resulting in a report indicating the radon measurements and advised action.

If radon levels are below 300Bq/M3 then you must keep a copy of the results and review them after around 10 years or if there are any significant changes to the workplace structure or use. If the radon levels exceed 300Bq/M3 then proceed to Step 3.

Step 3 – Take Action to Reduce Radon Exposure

If you have radon measurements exceeding 300Bq/M3 then you will usually be advised by PHE or your specialist contractor of what action you should take to reduce the levels. Remediation action could mean engineered systems including improving under-floor and indoor ventilation, or installing a radon sump and extraction pipework. You will also be advised to complete another radon survey to be sure that the remediation levels are effective. You should also notify employees about the radon level and the actions you are taking to reduce it.

If your remediation action bring the radon level down to below the action level, then you should keep the measures in place, and re-test at a frequency advised by your specialist. If remediation doesn’t reduce the radon level below 300Bq/M3 then from 2018 you must notify HSE.

Step 4 – Review Your Radon Assessment

Radon assessments should be reviewed periodically. The British Geological Survey are constantly updating their database with new information as they learn more about the UK’s ‘Affected Areas’. As a minimum, if you are not in an affected area, do not have below-ground workplaces or survey measurements were well below action level, then you should review every 10 years. If your risk level is higher your specialist will advise you how often to review your assessment and/or controls.