Spain stands as the sole European Union member yet to transpose Directive 59/2013/EURATOM, which requires member states to measure and control radon in homes, schools, workplaces, and public buildings. A formal deadline was set four and a half years ago for launching a National Plan against Radon by February 6, 2018. In this context, a World War II–themed event organized by the Radon-Free Live initiative of the Geo-Environmental Health Institute gathered more than a dozen specialists to address this radioactive gas challenge. The National Radon Congress took place as part of these efforts.
Across the two days of the congress, radon emerged as a critical health concern. Classified as a group 1 carcinogen by the World Health Organization decades ago, it is identified as the second leading cause of lung cancer after tobacco, even among non-smokers.
For José Miguel Rodríguez, director of the Institute of Geoenvironmental Health, radon is a public health issue that the general population often underestimates, yet it can carry severe consequences for those exposed. He argued that the problem is entirely avoidable with proper action. He urged the government to actively publicize the existence of the risk and the available solutions, noting that current measures fall short. He pointed out that legislation and public information are lacking, which is why private enterprises offering radon-free environments continue to operate and why the congress is needed again this year.
Radon occurs naturally underground, especially in granite-rich regions where it seeps into the air. Large areas of Spain—Galicia, Extremadura, and the Sierras de Guadarrama and Gredos near Madrid—face this issue. Outdoors, the gas dilutes and is not a danger, but when it infiltrates buildings through cracks in basements and foundations, it can accumulate indoors, posing health risks to residents and workers. Studies suggest that more than 1,500 people in Spain die yearly from radon-related lung cancer, according to experts at universities and public health institutions.
There is no safe level of radon exposure
During the congress, discussions highlighted that health risks rise with radon concentrations. A notable threshold cited was 50 Bq/m3, where risk begins to increase, with higher risk at elevated exposures, particularly for smokers due to additive effects. The directive sets a reference level at 300 Bq/m3, though some European countries have chosen 100 or 200 Bq/m3 to better protect their citizens. Independent radon measurement experts emphasize that exposure limits can vary by country while recognizing that any detectable radon presence matters for health. Global health authorities have stressed the need for protective standards to safeguard the population.
Attendees underscored that there is no level of radon considered completely safe. Estimates show that the risk of developing lung cancer grows by about 16% with every additional 100 Bq/m3 of exposure, and there is a linear, statistically meaningful relationship between radon concentration and cancer risk. Some researchers report studies linking higher radon exposure to lower survival rates after lung cancer diagnosis.
Maps for planning public prevention policies
Radon maps remain among the most widely used tools to assess regional radon presence and to estimate potential risk levels. These maps, produced by institutions such as the Nuclear Safety Council and the Geoenvironmental Health Institute, guide policy makers in prioritizing protective actions. Yet experts warn that maps alone cannot precisely predict home-specific radon levels; they serve to identify priority zones for action and to structure prevention strategies. Individuals should always obtain precise measurements for their own properties when needed.
Researchers emphasize that prevention policies benefit from such maps while acknowledging that even homes in low-risk areas can harbor radon. Therefore, targeted testing is essential to ensure indoor air quality and reduce long-term cancer risk.
Laura Mezquita, an oncologist and researcher focusing on residential radon and cancer, stresses that prevention policies play a key role alongside emerging treatment modalities. Interventions that address preventable cancer risk factors, including radon, should be integral to the overall approach to cancer prevention.
Ignorance in the construction industry
Rodríguez notes a noticeable gap in radon knowledge, even among construction professionals. While the Technical Building Code includes requirements for radon safety in new buildings and renovations, many builders lack training. He points to examples from nearby countries such as the United Kingdom, Ireland, and Belgium, where governments have introduced home measurement schemes to improve awareness and action.
Additionally, the World Health Organization recommendations for residential radon levels are often viewed as a guide that informs national limits. Critics argue that higher national limits fail to offer adequate protection for health, particularly for individuals who are exposed for long periods. The dialogue emphasizes the need for a pragmatic approach: measure, assess, and remediate when necessary to ensure healthy indoor environments. The emphasis remains on practical steps that homeowners and business managers can take to mitigate exposure through professional assessment and appropriate remediation techniques.
Ultimately, the approach calls for recognizing radon as a measurable factor in indoor air quality. The goal is to empower households and workplaces to protect health through informed decisions and timely action. The path forward involves expert evaluation, public awareness, and policy alignment to reduce radon-related health risks across the country.
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