Heat and Work: The Danger of Heat Stress

With the arrival of summer and steadily rising temperatures, the risk of heat stress for workers is once again in the spotlight, especially for those employed in sectors such as construction, agriculture, logistics, and transportation. In an increasingly unpredictable climate marked by frequent and intense heat waves, institutions are strengthening regulatory and operational frameworks to protect health and safety in the workplace.

What is Heat Stress?

According to definitions provided by INAIL (Italian National Institute for Insurance against Accidents at Work), heat stress occurs when a worker’s body experiences an imbalance between internal heat production—especially during physical activity—and heat exchange with the external environment. If the body is unable to dissipate the excess heat, various health issues—some potentially severe—can arise, such as heat stroke, dehydration, and muscle cramps. On the other hand, extreme cold can also be dangerous, potentially leading to hypothermia or frostbite.

The risk of heat stress is closely linked to the microclimate. This refers to the combination of environmental factors that affect thermal comfort: air temperature, relative humidity, air velocity, and mean radiant temperature. Based on these elements, INAIL distinguishes between moderate environments, where the goal is thermal comfort, and harsh environments, where heat stress poses a real threat to workers’ health.

The New INAIL-CNR 2024 Guidelines

In 2024, INAIL, in collaboration with the National Research Council CNR, updated its operational guidelines for addressing heat stress as part of the (Worklimate Project). The update responds to the need to provide more effective and up-to-date tools for Prevention and Protection Service Managers (RSPP), occupational physicians, employers, and safety coordinators.

Key Updates Include:

• Introduction of the WBGT Index (Wet Bulb Globe Temperature): An integrated index that measures the combined effect of temperature, humidity, solar radiation, and wind on the human body.
  
• New health surveillance procedures: Monitoring protocols tailored for vulnerable individuals, such as older workers, employees with cardiovascular conditions, and newly hired staff.
  
• Digital tools for real-time risk assessment: Apps and updated weather portals connected to bulletins from the Ministry of Health and Civil Protection.
  
• Operational guidelines for adjusting work schedules: Recommendations to shift working hours earlier or later to avoid the hottest part of the day (between 12:00 PM and 4:00 PM).

Legal Obligations and Protections

The Italian legal framework provides clear protections regarding health and safety at work, with specific references found in:

• The Italian Constitution, in Articles 32, 35, and 41, establishes the right to health as a fundamental interest, taking precedence even over business freedom.
• Legislative Decree 81/2008, which requires employers to assess microclimate-related risks and implement necessary measures to protect workers.
• Regional and ministerial guidelines, which, during heatwaves, may lead to the temporary suspension of work activities, particularly in construction sites and agricultural fields.

Additionally,  Circular No. 6 of March 18, 2022, issued by the Ministry of Labor and Social Policies, clarifies the use of social safety nets in cases where work is suspended due to “extreme heat risks.” This provision allows employers to activate the Ordinary Wage Guarantee Fund (CIGO) without needing to prove exceptional events, as long as the risk is supported by official weather bulletins.

Practical Measures and Recommendations

To reduce the risk of heat stress, companies are encouraged to implement preventive measures such as:

• Providing fresh drinking water and shaded areas for breaks
• Using breathable technical clothing
• Scheduling work shifts to avoid the hottest hours of the day
• Training staff to recognize the symptoms of heat stress
• Installing fans, air conditioners, or cooling systems where feasible

The National Council of the Order of Psychologists (CNOP) also highlights the psychological effects of heat stress. These can include increased anxiety, irritability, and cognitive difficulties—factors that may negatively impact both safety and productivity in the workplace

Heat stress is not merely a matter of discomfort—it is a real occupational hazard that can have serious consequences for workers’ health and safety. New guidelines and regulations have strengthened the tools available to employers and employees, but what’s truly needed is a cultural shift: prevention is a shared responsibility.

With rising average temperatures and the increasing frequency of extreme weather events, managing microclimatic risk is set to become a permanent priority in every workplace.