Too Hot at Work? Here’s What Your Employees Are Entitled To
July 2026 - Summer temperatures are soaring. For those who work in an office, a fan or air conditioning is often enough to get through the workday. But for employees who work outdoors or perform heavy physical labor, extreme heat can pose a serious health risk. That’s why Belgian law imposes a number of clear obligations on employers as soon as it gets too hot in the workplace.
It’s not the regular temperature that counts, but the WBGT index
Many people think there’s a fixed outdoor temperature at which employers must take action. That’s not the case. The law uses the so-called WBGT index (Wet Bulb Globe Temperature). This index takes into account not only the air temperature but also humidity, solar radiation, and air circulation. As a result, the WBGT index provides a much more realistic picture of the heat stress to which employees are exposed.
The action thresholds vary depending on the physical demands of the work:
Physical strain:
Very light or light work: 29 °C
Moderately strenuous work: 26 °C
Heavy labor: 22 °C
Extremely heavy labor: 18 °C
Secretarial work, for example, is considered light work, whereas groundwork or other physically demanding outdoor activities reach the legal limit much more quickly.
What measures must an employer take?
If the legal thresholds are exceeded, the employer is required to take measures to protect the health of employees.
Among other things, the employer must:
· protect employees from direct sunlight, for example with sunshades, awnings, or headgear
· provide free, refreshing, and appropriate beverages
· adjust the workstation and work organization where possible
· if necessary, provide additional ventilation or cooling in the work areas within 48 hours
· provide rest breaks when the heat stress remains too high.
The frequency and duration of these rest breaks depend on the risk assessment, the nature of the work, and the duration of exposure.
Risk Assessment Is Mandatory
Employers must not wait until employees complain about the heat. The Codex on Well-Being at Work requires them to conduct a risk assessment in advance for work activities in which employees may be exposed to high temperatures. Based on this assessment, preventive measures must be developed and, if necessary, adjusted as soon as weather conditions change.
The prevention advisor and the occupational physician also play an important role in this regard. They can advise on what measures are necessary and inform employees about the health risks.
What if it remains too hot?
If conditions remain problematic despite all measures, the employer may decide to temporarily suspend work. In certain sectors, a temporary unemployment scheme may be applied for this purpose. Employees then receive unemployment benefits, which in some sectors are supplemented by a livelihood security fund.
Ozone Also Deserves Attention
Extreme heat is often accompanied by elevated ozone concentrations. Outdoor workers, in particular, may experience shortness of breath, eye and throat irritation, or headaches as a result.
Although there is no separate legal regulation specifically addressing ozone, employers must also incorporate this risk into their wellness policies.
Possible measures include:
· scheduling heavy physical labor in the morning whenever possible
· avoiding overtime during ozone peaks
· working in the shade or indoors more often
· providing additional rest breaks indoors
· limiting additional exposure to irritants.
Employees Do Not Have to Simply Endure the Heat
Minister of Labor David Clarinval emphasizes that the rules regarding working in extreme heat are not merely non-binding recommendations, but legal obligations. As soon as the legal thresholds are exceeded, employers must take appropriate protective measures. Anyone who notices that the heat in the workplace poses a risk and that no action is being taken can discuss this with their employer, the occupational safety and health advisor, or the occupational physician. Compliance with the rules can also be monitored by the Occupational Health and Safety Inspectorate.
