Radon emits ionizing radiation due to the natural decay of uranium 238 which is part of the rocks of the earth’s crust. From underground it rises and can seep into homes and workplaces through cracks, fissures and poorly sealed joints. Sometimes it reaches concentrations dangerous to health. It is therefore appropriate to ask ourselves how much radon is present in our homes and workplaces.
Radon is a type I human carcinogen (demonstrated association) causally linked to lung cancer. The relationship between exposure to radon and the risk of this type of cancer is dose-response: the greater the exposure, the higher the risk. The first studies were carried out in miners over the last century, then in the general population until confirming that people exposed to high concentrations of radon in their homes had a higher risk of lung cancer.
Many factors influence the concentration of radon in indoor spaces, but the most important is the uranium content of the rocks in the Earth’s crust on which buildings rest and the degree of insulation of the building from the soil.
Spain is slow to apply European directives
In 2013, the European Union published the Directive on Protection against Ionizing Radiation, which set an application period until February 2018. In addition, it set a maximum reference level of 300 becquerels per cubic meter (Bq/m³) for homes and workplaces. , among other aspects.
Spain implemented this directive very late, in December 2022, with a royal decree that requires employers to protect workers from exposure to radon. Concretely, it requires that it be measured in all underground workplaces, through laboratories accredited by the National Accreditation Entity (ENAC).
In addition, in municipalities in priority areas, it is necessary to carry out measurements on the ground floor. Priority areas should be indicated by the Nuclear Safety Council. We are currently awaiting the designation of these locations. Everything seems to indicate that these will be those indicated as type II by the Technical Building Code, located mainly in Galicia, Madrid, Extremadura, Castile and León and Catalonia.
In the event that radon levels exceed 300 Bq/m³, the Royal Decree requires that mitigation actions be implemented to protect and reduce worker exposure.
Is radon exposure high at work?
The most in-depth study carried out in Spain on this subject was published in 2023. It includes data on 3,140 jobs in 14 Spanish provinces, although the majority are located in Galicia.
In our work, one in five uses exceeded 300 Bq/m3. Differences were observed depending on the sectors: those most exposed to radon were the cultural and educational sectors; the least, finance and textiles. As expected, the concentration of the gas decreases as the station moves away from the basement: 30% of workers in the basement would have exposures greater than 300 Bq/m³, compared to 17% on the first floors.
The geographical location of the workspace according to the classification of the municipality is also essential. While 21% of locations in municipalities with high radon potential exceeded 300 Bq/m³, this percentage was only 1% when located in other areas.
It should be noted that extreme radon concentrations, above 1000 Bq/m³, were found in 4% of all workplaces included in this study.
How much of a health risk does this pose?
Available evidence indicates that the relationship between radon and lung cancer is linear. The latency period between exposure to the gas and the onset of symptoms can span decades (at least 20 years of high exposure), so the risk of lung cancer can increase significantly.
We also know that there is a significant interaction between radon exposure and tobacco use. In fact, most cases of lung cancer attributed to radon occur in smokers and former smokers. Thus, if the exposed person has never smoked, their risk, although it exists, is lower than that of a smoker.
Finally, we must also consider the fact that the person exposed at work may have a high concentration of radon in their home. Especially if you live in an area with high radon potential and on the ground floor.
This does not eliminate the employer’s current obligation to assess and reduce the concentration of this gas as effectively and quickly as possible. This can be achieved, in the vast majority of situations, in a simple manner.
In short, the measurement of radon gas and its mitigation (if applicable) constitute an obligation on the part of employers in the context of protecting the health of workers. Fortunately, we know how it is measured, how it is reduced, and how it affects health. There is no longer any excuse to enforce regulations and achieve a healthier work environment in the face of a carcinogen that has always been there, but to which not enough attention has been paid.
This article was originally published in The conversation. You can read it here.
