Management of heat waves: obligations of the employer

Verified 26 June 2026 - Entreprendre Service Public / (Prime Minister)

Hot spells disrupt working conditions and significantly increase the risk of accidents at work. When the meteorological vigilance thresholds are reached, the employer must supplement the usual preventive measures with specific actions adapted to the alert level. We present all these measures as well as possible compensation schemes in case of cessation or reduction of activity.

FYI  

The term « heat wave » is a generic term that refers to a period during which temperatures can pose a health risk to the population. It covers situations of heat peak, persistent heat episodes, heatwave.

The Labor Code does not set any maximum temperature beyond which it would be prohibited or dangerous to work. For theINRS: titleContent, the vigilance threshold is 30 °C for office work and 28 °C for outdoor work.

However, the employer must incorporate this risk into the single occupational risk assessment documentmonitor changes in weather conditions and adjust preventive measures accordingly.

Obligations in case of high heat

The employer must guarantee the health and safety of employees. In case of high heat, it shall in particular:

  • Provide employees with fresh drinking water to allow them to quench their thirst and cool down
  • Evaluate positions and not assign young people to works that exposes them to high temperatures that could harm their health
  • Implement climate protection measures for employees working outside the workplace
  • Temporarily assign a pregnant employee to another position when the heat makes the initial position risky, on her own initiative or if the employee requests it.

Increased obligations in case of intense heat

In case of episodes of intense heat, the employer shall reassess risks (indoor or outdoor) and adapt prevention measures and actions.

The reinforced system is based on the vigilance thresholds of Météo‑France (yellow, orange and red thresholds). When they are achieved, the employer must reassess the risks incurred by its employees, with the help of staff representatives.

FYI  

  • Green vigilance : seasonal watch without particular vigilance
  • Yellow vigilance : heat peak (exposure over a period of 1 to 2 days to intense heat presenting a risk to human health because of working conditions or their physical activity)
  • Vigilance orange : heatwave period (intense and long-lasting heat that could pose a health risk to the entire exposed population)
  • Red vigilance : period of extreme heat waves (exceptional heat waves in terms of duration, intensity and geographical scope, which have a strong health impact on the entire population or could lead to the appearance of side effects of business continuity)

If the risk assessment reveals a danger to the health or safety of employees, it must integrating risk into the single occupational risk assessment document (DUERP) and adapt prevention measures and actions usual.

In concrete terms, the company can:

  • Set up working methods limiting or avoiding exposure to heat
  • Design the premises and posts work (refreshed or converted premises), prioritize teleworking if possible
  • Adapt schedules to limit the duration and intensity of exposure to heat and to provide rest periods
  • Set up technical means to reduce solar radiation on exposed surfaces or to prevent the accumulation of heat in work spaces (sun visors, fans, mist...) sprayers
  • Provide fresh areas and limit or delete certain tasks
  • If necessary, increase the amount of fresh drinking water provision to employees (individual water bottles or water point with cups)
  • Ensure that personal protective equipment (PPE) are compatible with high heat (breathable or cooling clothing)

Please note

If the employee is free to dress as he wishes, the employer may, however, restrict this freedom if the nature of the work or the proper functioning of the company so requires (for example for reasons of safety, hygiene, organization...).) In these situations, the rules are formalized in the rules and regulations or the employment contract.

  • Informing employees about risks heat-related (dehydration, heat stroke...)) and on preventive measures to be adopted
  • Enhancing vigilance vis-à-vis exposed employees, especially the most vulnerable because of their age or health condition

FYI  

If necessary, the employer may request its prevention and occupational health service.

These measures must be adapted to changing climatic conditions. The employer must therefore be attentive to the information and alerts disseminated by the authorities during the period of vigilance. In the event of a "red alert" by Météo France, the employer must carry out a risk reassessment every day.

THEAdeme: titleContent and theINRS: titleContent have developed a website that can offer employers tools to anticipate major risks, prevent accidents at work and adapt their organizations.

Website « Fresher at work »

Ecological Transition Agency (Ademe)

Pour en savoir plus

Warning  

THElabor inspection may give formal notice to the employer take preventive measures or actions against occupational risks related to intense heat episodes.

On the construction sites of building and Public works and in the agricultural sector, workers are more exposed to high temperatures (outdoor work, sustained physical exertion, low possibility of changing the working environment). These sectors therefore require the employer to be more vigilant and to adapt its behavior to the heat episodes.

It must assess the risks and, if necessary, postpone activity, adapt schedules (start earlier, finish later, avoid the hottest hours).

It must also make available to employees:

  • A place of rest sheltered from the heat
  • Handling aids
  • Of PPE: titleContent and workwear adapted to high temperatures.

FYI  

When running water cannot be put in place, the amount of water made available is at least 3 liters per day per worker (or more if necessary, depending on the intensity of physical activity).

On construction sites, the general coordination plan and the special plan for safety and health protection shall take into account the risks associated with exposure to intense heat events.

If the measures taken are insufficient, the employer must stop the works.

FYI  

The preventive measures provided for employees are applicable to self-employed and to employers directly involved in certain work sites : building and civil engineering sites, forestry sites, works in high trees, felling, pruning, disconnecting, shredding and grinding operations.

If the activity is disturbed, in case of orange or red alert companies may activate certain devices:

FAQ