Radon is a naturally occurring radioactive gas that forms in the ground through the radioactive decay of uranium present in rocks. The radon isotope (Rn-222) is one of the radioactive products of the uranium-238 decay series and its characteristic is that it is the only element in gaseous form in this series. Radon can therefore, unlike the other solid elements, be released from rocks, diffuse through the ground and then be inhaled in living environments.
Radon is an odorless, colorless and tasteless gas; all characteristics that make it imperceptible to our senses and therefore difficult to detect and quantify.
The greatest danger of radon gas is related to inhalation: if inhaled in excessive quantities and for prolonged periods, it can in fact cause serious damage to health, particularly to the lungs, ranking as the second risk factor for the onset of cancer, after smoking.
In enclosed environments, especially in rooms in contact with the ground, radon can accumulate, reaching very high concentrations when air exchange is limited. Radon enters rooms through cracks, fissures or openings in the foundations. Workplaces in basements, semi-basements or sometimes even on the ground floor are particularly affected by this phenomenon (archives, warehouses, canteens, changing rooms, etc.).
The Employer is required to carry out an assessment of all risks present in the work activity pursuant to art. 28 of Legislative Decree 81/08 and therefore also of the risk deriving from exposure to radon gas (ionizing radiation, Title VIII of Legislative Decree 81/08), where it is specified that the protection of workers from ionizing radiation is governed, in compliance with the principles set out in Title I, by the special provisions on the matter (Legislative Decree 101/2020).
Legislative Decree no. 101, published on 31 July 2020 and entered into force on 27 August 2020, introduced important changes regarding the prevention of and protection from ionizing radiation, with the aim of adapting Italian legislation to the provisions established at European level.
Art. 12 of Legislative Decree 101/2020 regulates the maximum radon concentration levels in homes and workplaces. In the latter case, the annual average concentration of radon in air is set at 300 Bq/mÂł.
Measurements must be carried out in companies:
- in underground workplaces;
- in workplaces in semi-underground premises;
- in premises located on the ground floor if situated in priority areas for the reduction of radon gas concentration levels;
- in specific types of workplaces to be identified in the National Radon Action Plan and in thermal establishments.
Legislative Decree 25 November 2022 no. 203, concerning supplementary and corrective provisions to Legislative Decree 101/2020, was published in Official Gazette no. 2 of 03.01.2022.
In particular, in art. 7 “definitions”, the new definition of underground workplace was introduced: a room or environment with at least three walls below ground level, regardless of whether or not they are in direct contact with the surrounding ground.
The first assessment of the annual average concentration of Radon activity must be carried out within 24 months from the start of the activity or from the definition of the risk areas or from the identification of the specific types in the National Plan.
The operator must repeat the measurements every eight years, if the concentration value is below 300 Bq m3, and whenever extraordinary maintenance, restoration and conservative rehabilitation, and building renovation works involving structural work at ground connection level are carried out, as well as interventions aimed at improving thermal insulation. If the annual average radon concentration in air exceeds the reference level of 300 Bq m3, the adoption of “corrective measures” aimed at reducing average indoor radon levels is required.
On 12 January 2023, Resolution no. 61-6054 of the Regional Council of Piedmont was published in the Official Gazette, identifying the priority areas for Radon risk (pursuant to Article 11, paragraph 3, of Legislative Decree 101/2020).
Priority areas are areas of the regional territory that are potentially more critical for exposure to radon gas, where it is estimated that the reference level for the annual average radon concentration is exceeded in a significant number of buildings.
The identification of priority areas entails, for Employers, the obligation to assess radon risk in all premises located on ground floors, semi-basements and basements.
In the resolution of the Piedmont Region, the following municipalities were identified as “priority areas”:
| Andorno Micca | Melle |
| Angrogna | Moiola |
| Aurano | Noasca |
| Bellinzago Novarese | Oleggio Castello |
| Bognanco | Pagno |
| Brondello | Perosa Argentina |
| Brossasco | Peveragno |
| Buriasco | Quargnento |
| Campiglia Cervo | Re |
| Candelo | Roccavione |
| Cannobbio | Rosazza |
| Ceresole Reale | Roure |
| Chiusa di Pesio | Santa Maria Maggiore |
| Druogno | Traversella |
| Entracque | Venasca |
| Gaglianico | Vigliano Biellese |
| Gaiola | Villar Pellice |
| Gifflenga | Vinadio |
| Macugnaga |
The resolution also identifies “Areas of attention”, meaning those areas which, while not falling within the definition of priority areas, involve a non-negligible radon risk within them.
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