Measurements to map the effects of exposure on workers and improve protection
An international consortium of TNO, NGO La Isla Network, sector organization Volandis, and construction and infrastructure companies is investigating heat and sun exposure for workers in the construction and infrastructure sector. The goal is to map how the risks can be properly assessed and managed for workers in those sectors. This week, measurements begin at construction sites of building company Van Wijnen. The research, funded by ZonMw, will deliver concrete advice and tools for occupational health professionals and workers to better protect the health of personnel at Dutch construction sites.
Heatwaves are becoming more frequent, longer-lasting, and more intense. UV radiation is also increasing. People who work outdoors already face serious risks of health problems, illness, and accidents due to heat and UV radiation, both acute and long-term. The health and labor productivity of people who work outside, such as roofers, asphalt workers, carpenters, and other tradespeople, are therefore under pressure.
Anjoeka Pronk, researcher at TNO: “Research that TNO conducted last year on behalf of KWF showed that UV radiation from sunlight is the single largest cause of work-related cancer in the Netherlands. This underscores the importance of better methods to assess and control UV exposure in the workplace.”
300,000 workers experience heat stress
Research by TNO from 2025 shows that more than 300,000 workers in the Netherlands are regularly exposed to heat stress in the workplace, including more than 20,000 people in construction. Globally, more than 639 billion working hours were lost to heat at work in 2024. In a recent advisory on policy directions related to climate change, the Health Council recommends better anchoring climate risks in occupational health and safety policy. In addition to introducing limit values for heat and UV, the advisory explicitly calls for better mapping of these occupational risks and how to manage them. This project contributes to that goal.
“Where heat is immediately felt, UV radiation is not. And that is precisely what makes it dangerous. Both risks are increasing, yet employers still lack the tools and clear guidelines to manage them on a daily basis.”
Approach to assessing and managing risks
The consortium is developing a practical approach that directly translates weather data and KNMI indicators for heat and solar intensity into concrete risks on the work floor. The system looks not only at temperature, but also at factors such as workload, wind, humidity, clothing, and the degree of acclimatization. This gives employers and occupational health professionals clear tools to properly assess heat load, manage risks, and keep workers healthy and safe on the job.
Matthijs Nieuwenhuis, Director European Development at La Isla Network: “The heat is rising fast, and that is a serious danger, especially for people who work hard in the heat every day. It is time to protect them. No one should get sick because of the work they do. The good news is that this is preventable. That is why this research is essential, and it is encouraging that the construction sector is taking it seriously.”
For companies in the construction and infrastructure sector, the approach offers a set of guidelines and recommendations for use in work preparation and planning. During work, it also functions as an early warning system, enabling companies to identify risks in time and prevent incidents. Although the development focuses on the construction and infrastructure sector, other sectors in which people work outdoors or in warm conditions will also benefit. Companies in Northern Europe with comparable weather and working conditions can apply the system as well.
The consortium is also developing practical tools and materials, including learning modules on measuring heat and UV radiation, checklists for occupational health professionals, and information materials for workers.
The construction sector takes the lead
Construction companies are opening their sites and involving their workers in the research. This week, researchers from TNO and La Isla Network are at work on several construction sites across the Netherlands, including those of Van Wijnen. The work takes place at residential construction and road works. Using wearable sensors and proven measurement methods, they are mapping what workers on construction sites actually experience: measuring how hot and sunny conditions are on site, how heavily the work loads the body, how high workers’ body temperatures rise, whether people are drinking enough, and how they behave when it is hot. Sector organization Volandis ensures that the findings are shared further with companies across the Netherlands.
Bas Roordink, Director of Safety at Van Wijnen:
“Increasing heat and UV radiation are bringing growing risks for everyone who works outdoors. With this research, we are taking an important step toward better insight and better solutions. Because working safely, now and in the future, requires knowledge, collaboration, and targeted measures. The people on our work sites deserve protection that is effective and keeps pace with a changing climate.”
Volandis: Fred Boots, occupational physician at Volandis, emphasizes the importance of this research for the entire sector and how the findings will reach the construction and infrastructure industry. “It is especially important to point employers and workers toward three measures they can take to work safely in heat: shelter, clothing, sunscreen. The outcomes of this research will make it possible to apply these measures even more effectively.”
END OF PRESS RELEASE
About the partners
TNO is the largest independent research and technology organization in the Netherlands and one of the largest in Europe. By innovating and orchestrating (inter)national consortia and ecosystems, it creates technological and methodological breakthroughs that strengthen the earning capacity of the Dutch economy, contributing to a safe, sustainable, healthy, and digital society. TNO also informs government and society through rigorous scientific research and reliable measurements, providing a scientific foundation for decision-making. www.tno.nl
La Isla Network is an international NGO and research organization in the field of occupational health and safety, focused on preventing heat-related illness among workers worldwide across sectors including construction, agriculture, transport, manufacturing, and mining. laislanetwork.org
Volandis is the knowledge and advisory institute for the Dutch construction and infrastructure sector, focused on healthy and sustainable working conditions. www.volandis.nl
Van Wijnen is a Dutch construction company that builds homes, neighborhoods, and workplaces with a focus on quality, sustainability, and future value. www.vanwijnen.nl
ZonMw is the Netherlands Organization for Health Research and Development, funding research and promoting the application of knowledge. www.zonmw.nl
Media contacts
- La Isla Network (international): Alfredo Moreno, Director of Communications · Click to reveal
- La Isla Network (Europe and Netherlands): Matthijs Nieuwenhuis · Click to reveal · +31 6 19351975
- Volandis: Twan Epe · Click to reveal
- TNO: Anjoeka Pronk · Click to reveal
- Van Wijnen: Mark Denslagen · Click to reveal
