As part of the European continent undergoes its fourth heatwave of 2026, it has become abundantly clear that occupational heat exposure is no longer an exceptional or occasional summer hazard. It is an emergent occupational hazard only destined to escalate. Europe is the second fastest-warming region of the globe after the Arctic. According to EU-OSHA 2025 numbers, one in five workers in the EU signaled exposure to extreme heat at work in the previous 12 months, a figure rising to one in three in some countries.
The ways in which prolonged or acute heat is a threat for the human population is well-documented. Prolonged exposure can lead to several disorders or illnesses in the short-term: rashes, oedema, syncope (or fainting), cramps, exhaustion, and heatstroke which can be fatal. Symptoms of heat exhaustion and heatstrokes include dizziness, headache, nausea, fainting, dehydration, confusion, high heart rate. In the medium-term, accumulated heat exposure can affect behaviour and cognition, causing stress and irritability and reduced cognitive performance. The latter, also called ‘fatigue’, typically leads to slower reaction time and increases the risks of accidents. In the long-term, impacts on health include an increased risk of cardiovascular, respiratory and other illnesses as well as psychosocial risks such as anxiety or depression.
Occupational heat stress, or workplace heat stress is measured by looking at three factors together – direct environment exposure, metabolic heat from performing physical activities, and thermal insulation (for instance coming from personal protective equipment). Several metrics have been designed to assess workplace heat stress, the most commonly used being the ‘wet bulb globe temperature’ (WGBT). The WGBT is calculated based on the dry-bulb temperature (‘air temperature’), humidity, wind speed and radiant heat. Its final value takes into account work intensity and thermal insulation from clothing and PPE. Therefore, occupational heat stress cannot be reduced to the question of the temperature of the air or sun exposure alone; the total heat load experienced by a worker performing a particular task in a particular setting must be considered. In this sense, an OSH response to heat risks focusing solely on workers operating outdoors in the sun misses a significant part of occupational heat risks.
It is important to note that exposure to heat stress does not in itself generate vulnerability; job exposure factors always interact with workers’ physiological factors, labour-market security factors and work organization factors. In practice, this means that some groups of workers are more exposed than others: migrant and self-employed workers may have lower levels of social protection, as well as lower unionization and access to information. Women workers, disabled workers or workers with a pre-existing condition tend to face higher risks due to physiological factors. Particularly relevant with regards transport’s aging workforce is the increased vulnerability of older workers, who are generally more susceptible to dehydration and may carry chronic cardiovascular, respiratory or kidney conditions (ETUI 2021 p23). This also means that two organisations experiencing the same heat exposure with similar profiles of workforce, can adopt different strategies to respond to heat stress, with very different outcomes (for instance, an organization choosing to reorganize work shifts to minimize exposition in the hottest hours of the day would attenuate its workers’ vulnerability). To sum up, occupational heat stress is measurable and preventable.
This article looks at the ways in which workplace heat stress materialises across transport occupations, lists existing ways to tackle the issue and proposes actionable recommendations for Trade Unions, employers and policymakers to strengthen workers’ protection.
Transport systems are vulnerable to severe heat and other extreme weather events. This concerns both infrastructure and workers. The impact on transport operations is the one most visible and most addressed, yet risks caused by heat on transport workers’ safety and health are just as crucial. Eurofound figures place transport at the third place of sectors most affected, with 33% of surveyed workers reporting exposure to high temperatures a quarter or more of the time (behind agriculture and construction, at respectively 68% and 52%, and on par with industry at 33%).
All the physiological and psychosocial risks on human health cited in the introduction apply to transport workers. The reduced cognitive performance or ‘fatigue’ brought by accumulated heat exposure, takes a particular gravity for professions in charge of driving vehicles or operating heavy machinery, where an error can be fatal. The psychosocial and physiological consequences of transport disruptions – delays, sudden changes in work patterns, increased workload, frustrated third parties – must not be underestimated.
Occupational heat stress may manifest in the following transport occupations in the following ways:
Courier and last-mile delivery workers often operate outside, directly exposed to the sun as well as thermal radiations from asphalt or concrete roads. For those on bikes, their heat stress from environmental thermal exposure is compounded by the metabolic heat gained by cycling. In food delivery, lunchtime is peak activity time, which is also when UV levels and temperatures are highest. Work is generally precarious, with widespread (bogus) self-employment and temporary agency work, third-country nationals making up a significant portion of the workforce, and low unionisation rates.
In warehouses and other logistics jobs, the inadequacy of AC systems, coupled with the loading and unloading at a fast pace, can lead to occupational heat stress. The common use of subcontracting, the presence of different employers in a single worksite, and the presence of third-country nationals are other elements pointing to an increased vulnerability of these workers.
Fishing is one of the most dangerous occupations there are, a situation aggravated by extreme weather conditions, heat included. Fishers do heavy work with prolonged exposure to sunlight and high temperatures. The safety equipment they are required to wear even increases their metabolic heat, and the sudden temperature change from moving back and forth between the freezer areas to store the catch and outdoors areas must not be underestimated. Navigating time does not offer much shelter from heat exposure as cabins often lack air conditioning (AC) systems.
Seafarers face some of the same challenges fishers do. Deck crew work in direct solar exposure, often wearing personal protective equipment that adds thermal insulation while galley and catering staff face a combination of thermal radiation from appliances, humidity and sustained heavy work in enclosed spaces.
Dockworker, terminal worker, crane operator, mooring personnel and other port professions are dangerous and demanding jobs. ETF affiliates in Italy, Belgium and Finland list some of the job factors that increase vulnerability to extreme heat episodes: those jobs require working outdoors for long periods, often with direct solar radiation, high temperature and humidity, thermal radiation from concrete surfaces and containers, and sometimes manually handling heavy cargo.
Regarding ground handling staff, ETF affiliates in Spain, France, Italy and the Netherlands have raised the alarm on heat risks affecting workers performing duties on the airport tarmac. This includes ground handling personnel, ramp coordinators and aircraft maintenance technicians. Employees work in direct sunlight, on hot concrete and asphalt surfaces, with radiant heat from aircraft engines and auxiliary power units (APUs), performing heavy physical work and often have to wear thick protective equipment. In periods of heatwaves, the APU is on in order to maintain AC in the aircraft cabin, and it releases air at 130°C. In the airport of Paris Charles de Gaulle, where more than 900 companies work, including subcontractors, each company provides a dedicated room for its employees to cool down; when that room is localized at the other end of the terminal to where one is working, one does not have the time to go take a break. During high heat periods, refuelers are supposed to spend a maximum of 90 consecutive minutes working outside, a rule nearly impossible to follow in practice as refuelers routinely have to stay outside 3 hours.
Aircrew and Air Traffic Management staff, though mostly working inside, also feel the effects of increased outdoors temperature. Aircrew generally works inside an aircraft cabin, which is an enclosed indoor environment. If an aircraft is parked in extreme heat under direct sunlight, the cabin temperature can rise significantly. Heat can also enter the aircraft through the open door from the jet bridge or directly from the tarmac. During boarding and disembarkation, the cabin may become extremely hot and poorly ventilated if air conditioning is unavailable or ineffective due to the absence or malfunction of the Auxiliary Power Unit (APU) or Ground Power Unit (GPU). After takeoff, the cabin may remain uncomfortably warm for an extended period if the air conditioning system is not performing adequately. In addition, the presence of many passengers in a relatively small and enclosed space can make the environment feel even hotter and more uncomfortable.
With short turnarounds, passengers may be made to wait to board on the tarmac or in very warm jet bridges. Heat stress frequently causes passenger agitation, discomfort, and occasionally fainting. Flight attendants are often required to assist affected passengers while working in the same overheated conditions.
Uniforms are rarely adapted for hot weather. A uniform usually is made from a synthetic fabric and often includes a jacket, a tie or neck scarf, and pantyhose, further increasing thermal discomfort.
In air traffic control towers, efficient AC is critical, as the sun going through very large glass windows makes the inside temperature rise extremely quickly.
Heat is a major occupational health and safety concern for road drivers in Europe. In particular, truck and lorry drivers face the unique situation that their workplace can also be the place where they live, as EU driving and rest rules make it possible to sleep in the cab. In episodes of extreme heat, drivers on a long distance journey have few options to escape the heat.
Urban Public Transport (UPT – Bus, tram and metro) workers are exposed to multiple occupational heat hazards, and as public transport workers, are often required to ensure continuity of the service during extreme heat episodes. The availability and adequacy of AC and ventilation in vehicles, depots or stations is an important issue. In Luxembourg, drivers commonly have to work without AC. Where there is AC in a vehicle, it is rarely adapted to the kind of intense, continuous use necessary during heatwaves. The systems often break down and have to be repaired. Similarly to road drivers, the lack of access to water and sanitation for mobile UPT staff is always a challenge, which worsens during heatwaves and increases the risk of dehydration. Many vehicles were procured when extreme heatwaves were less common, around 10-15 years ago, meaning their climate control systems are not sufficiently powerful to keep drivers and passengers safe. Several European metro systems, notably the London Underground, do not have sufficient cooling capacities, having been built before severe heat was a persistent problem.
In railway, it is common to see stories of passengers trains cancelled en bloc make the news during heatwaves. This is often the case because extremely high temperatures create a risk of track buckling, i.e. the expansion of steel rail, causing it to bend, which has the potential to derail trains. In addition to directly threatening the safety of operations, track buckling and its preventive and adaptative response – cancelling, slowing down or rerouting – also leaves railways workers having to deal with frustrated passengers. Heat may also affect railway workers in the following ways:
Climate change exposes transport workers to a series of hazards, of which increased heat and heatwaves are only a facet. Sudden or extreme weather events take many forms, as dangerous as heat can be: cold waves, heavy precipitation, floods, storms or cyclones. By their intensity or their suddenness, all are disruptive and potentially dangerous for transport networks and transport workers. It is also worth noting prolonged heat increases the risk of droughts, and the two combined together with moderate to high winds create the perfect conditions for the occurrence of wildfires and sand and dust storms, which also expose workers to smoke and air pollution.
While the succession of extreme heat episodes gives a sense of urgency to the need to mitigate and adapt to the occupational heat risk, the sustained increment in global temperature is just as much of an issue. Recent research compiled by Laabas-el-Guennouni and Flouris (ETUI 2026 p25) shows that humans’ productivity peaks in a working environment of about 15°C WBGT, and that productivity declines with each 1°C WBGT increase beyond 15°C. In this sense, there is no need to reach the threshold of a heatwave for workers’ health to be endangered.
Several policy options exist to mitigate or adapt to heat stress, OSH-general or heat/climate-specific, at international, European, national, sectoral, or workplace level. No international treaty addresses specifically the impact of climate change on OSH. However, general and targeted international standards exist in the field of OSH which put obligations on employers or provide guidance, such as ILO C155 or, for the maritime sector, the Maritime Labour Convention regulation 4.3 and Standard A4.3. In the European Union (EU), the main framework governing occupational safety and health is the ‘Framework Directive’ 89/391/EEC of 1989. The Directive foresees a set of obligations on employers in the field of OSH, such as carrying out a risk assessment, adopting preventive and protective measures, organizing work to safeguard workers’ health and safety, and providing appropriate information and training to workers.
In many countries, there is no specific legislation to address occupational risks from heat or other extreme weather events, which are only covered by the general OSH framework (Finland, Hungary for instance). Instead of binding legislation, there may be protocols or guidance on climate-related occupational risks (Italy, Luxembourg) or it might be left to workplace assessments (Norway, Finland). In Spain, however, legislation does exist on outdoor work carried out under conditions of extreme heat. Royal Decree-Law 4/2023 requires employers to adapt working conditions whenever the National Meteorological Agency issues orange or red weather alerts, where preventive measures are insufficient to guarantee workers’ safety. This includes reducing or shifting working hours.
Collective agreements may contain measures to adapt to the occupational heat stress. In Hungary, the collective agreements of the Hungarian State railways include provisions for longer hourly rest breaks in hot conditions than those required by legislation. In the Port of Antwerp, in Belgium, dockers have an agreement over the WGBT. Two thresholds give right to recovery periods when exceeded: above 25.9 WBGT provides 20 minutes and above 27.6 WBGT provides 40 minutes of recovery time. The arrangement applies to everyone except those working in climate-controlled warehouses or cabins with functioning AC. JustEat Takeaway Italy signed an agreement with the trade unions with provisions for extreme heat periods: to stop to orders at peak times, have more paid breaks and protections for workers over 60 years of age. The agreement also foresees that workers will be paid during times that work is suspended. Although positive, this agreement only applies to directly employed staff of JET Italy, leaving behind the self-employed.
Occupational heat stress, and other weather-related occupational risks, need to be addressed through OSH legislation, workplace risk assessments, and, where appropriate, collective bargaining. Sectoral guidelines may be necessary. To Trade Unions, employers and policymakers, ETF recommends the following:
In periods of extreme heat: