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The risk of radon exposure must be taken into account by companies in their risk assessment.
That's why we've put together an overview of the main legal obligations in this area.
What is radon?
Radon is a naturally occurring radioactive gas produced by the decay of uranium and radium.
It forms underground and is classified as a carcinogen* ;
Radon is present throughout France, with high concentrations in granite and volcanic regions (Massif Armoricain, Massif Central, Corsica, Vosges, etc.).
*Studies show that radon exposure is the second leading cause of lung cancer in France, after tobacco.
The concentration of radon in the air of a building depends not only on the characteristics of the soil, but also on the building and its ventilation.
What is the reference level?
This is the level of radon activity concentration above which it is considered inappropriate to allow workers to be exposed to ionizing radiation, even if it is not a limit that cannot be exceeded.
It is set at an annual average of 300 Bq/m3.
How are communes classified?
The radon potential of communes is set by the decree of June 27, 2018 and listed on a map available on the IRSN (Institut de Radioprotection et de Sûreté Nucléaire) website. You will find the communes classified in 3 categories:
- Zone 1: areas with low radon potential ;
- Zone 2: areas with low radon potential but where particular geological factors may facilitate the transfer of radon to buildings;
- Zone 3: areas with significant radon potential.
Who is affected by Radon regulations in the workplace?
This applies to companies where workers (including the self-employed) are likely to be exposed to a risk from ionizing radiation of natural or artificial origin, and in particular to the following professional activities:
- in the basement or first floor of buildings located in areas where radon exposure is likely to be harmful to workers' health
- in certain specific workplaces listed in the Order of June 30, 2021 (underground mines and quarries, tunnels, underground parking lots, thermal baths, etc.).
These employers must assess the radon risk.
How do you assess radon risk outside specific locations?
How do you assess radon risk in specific locations?
The employer must set up an alert system, in the absence of an ambient radon monitoring system, for each worker or team of workers carrying out short-term work for which the prior radon risk assessment does not indicate that the reference level has been exceeded.
What should I do if I've identified a radon zone?
If a radon zone is identified, the employer must :
- appoint a radiation protection advisor ;
- indicate the radon zone;
- carry out initial verification by measuring the radon activity concentration in the air in radon zones when the facility is commissioned, or following any significant change in working conditions that may affect worker health and safety. This verification is carried out by an accredited body or a body approved by the ASN. In specific workplaces, if the employer decides to set up a radon zone for the entire workplace, an initial verification is not required.
- periodically renew this verification (at least every 5 years or, if radon activity exceeds 1000 Bq/m3, every year), which is then carried out by the radiation protection advisor;
- provide workers with personal protective equipment when collective protection is not sufficient;
- train exposed workers ;
- assess the personal exposure of workers accessing these areas prior to their assignment to the workstation, and issue them with authorization
- set up dosimetric monitoring of workers (using dosimeters with appropriate delayed reading) when the effective dose is likely to exceed 6 mSv over 12 months, and provide them with reinforced individual health monitoring.
What about ERP (Etablissements recevant du public)?
Additional obligations apply to certain ERP (prisons, thermal baths, education, etc.), such as :
- Periodic measurements by IRSN or approved organizations
- Corrective actions,
- Display of results, ...
Radon exposure: conclusion
All companies must consider the risk of radon exposure for their workers, and more specifically, record the results of their risk assessment in their single document.
Note: this assessment and the results of the measurements are to be forwarded to health professionals (occupational physician, collaborating physician, nurse, etc.) and to the Social and Economic Committee(CSE).
Photo credit: Luca Maffeis