Radon gas: A workplace hazard?

What is radon gas?

It is a chemical element with three important properties:

• Under normal conditions, this gas is released naturally by the radioactive decay of uranium in the ground and in rocks (granite has more uranium than other rocks, and therefore releases more radon). This allows it to build up in places where people are working, but it can also be spread through ventilation.
• It is a noble gas, so it it not normally involved in chemical reactions.
• It is radioactive, which means that it has significant effects on our health. It is produced by the decay of 226Ra, which is part of the 238U radioactive decay series, present in the Earth’s crust.

A health hazard

The ease with which it enters closed or underground spaces in buildings is matched by its ability to enter our lungs, and to transport radioactive particles there which can cause mutations in our cells and lead to cancerous tumours.

Radon is currently the second most common cause of lung cancer, after tobacco. Many “non-smokers” can develop this illness as a result of exposure to this radioactive gas. The problem is even greater for smokers because they combine the effects of exposure to both of these agents.

How can we monitor radon gas?

As a gas, radon can pass through any opening or gap, especially because it is emitted by the construction materials themselves. It can accumulate in any kind of building, but not to the same extent. This is why the regulation requires that certain workplaces carry out an annual average reading of radon concentration in the air. This requirement applies to the following categories of workplaces:

a) underground workplaces such as building sites, tunnels, mines and caves.

b) wherever underground water is processed, handled or used, such as thermal facilities and spas.

c) workplaces located at ground level or on the ground floor in municipal areas where it is a priority.

Radon gas in municipal areas where it is a priority

As we have seen, some towns must test all their workplaces, while other only need to test underground workplaces or ones related to subterranean activities. To find out if your workplace falls into one or the other category, you should consult a list published in a Nuclear Safety Council directive.

The Nuclear Safety Council draws on the National Plan against Radon when making these periodical lists. This is a document that must be updated every five years by the Ministry of Health.

One useful tool for the general public in this context is the Map of radon potential in Spain, published on the website of the Nuclear Safety Council. It shows all of Spain, using colours to indicate the radon potential in each area. The main concentrations are:

• On or near the coast of Catalonia, especially in the north-eastern parts of the province of Barcelona.
• Some areas in the Pyrenees, in Navarra, near Lerida and especially near Huesca.
• A significant part of the islands of Tenerife and Gran Canaria.
• Most of Galicia.
• Scattered points across the provinces of Asturias and Leon.
• Some areas, especially the most westerly parts, of the province of Zamora.
• A wide swathe of land around the Central System, the Montes de Toledo and Extremadura.
• Other areas in the westernmost part of Castile-La Mancha.
• Various zones in the north and east of Andalusia.
• Some spots in western Murcia.

Prevention in the workplace

It is important to understand the regulation. Some of the central aspects are laid down in  Royal Decree 1029/2022. This specifies the workplaces where readings must be taken and, where appropriate, those where there may be an obligation to take preventive action.

Another important aspect is the regular publication of national plans. Every five years, they state, among other aspects, the measures to identify workplaces where the average annual concentration of radon is higher than the set reference level. They also establish measures to help reduce radon concentrations, using technical or other means.

A secondary consideration, besides the regulation, is to set up measures to disperse radon and prevent it from returning. Some building work may be required to seal cracks or install chimneys to evacuate the radon.

In short, despite being invisible, radon is a gas with harmful and even deadly effects on our health. We must be vigilant and address any problems that arise by taking appropriate and effective action.