With multiple heatwaves, record-breaking temperatures and repeated heat-health alerts, businesses across the country are starting to realise that extreme heat is no longer an exceptional event. It has become a foreseeable workplace risk that requires active management, just like any other risk.
This means appropriate risk assessments, control measures and employee protections. Organisations that do not adapt to the increasing frequency of these heat events may expose workers to preventable health risks while also increasing their own legal and operational liabilities.
The figures
According to the Met Office, Summer 2026 saw unprecedented heat conditions, including multiple widespread heatwaves and, in certain areas of the UK, temperatures exceeding 35°C in May, June and July, the first time this has occurred in a single year. By mid-July, the UK had already recorded more days above 30°C than the whole of the famous summer of 1976.
The consequences
Needless to say, these conditions had practical consequences for employers. Outdoor workers faced prolonged exposure to high temperatures and solar radiation, while indoor workers in offices, warehouses, manufacturing facilities and healthcare environments experienced challenges keeping their working conditions safe and comfortable. The Health and Safety Executive (HSE) responded by reminding employers that risks arising from extreme heat must be assessed and managed in the same way as any other workplace hazard, through risk assessment and suitable controls.
What does the law say?
One of the most common misconceptions is that health and safety law specifies a maximum workplace temperature. In reality, there is no such statutory upper limit (although there is a lower limit). However, this does not mean employers have no obligations when temperatures rise.
The primary legal duties arise from:
- The Health and Safety at Work etc. Act 1974, which requires employers to ensure, so far as is reasonably practicable, the health, safety and welfare of employees.
- The Management of Health and Safety at Work Regulations 1999, which require employers to conduct suitable and sufficient risk assessments and implement appropriate control measures.
- The Workplace (Health, Safety and Welfare) Regulations 1992, which require indoor workplaces to maintain a reasonable temperature during working hours.
- The Construction (Design and Management) Regulations, which require protection from adverse weather on construction sites and appropriate welfare facilities.
Understanding heat-related risks
Heat affects people differently. Factors such as age, underlying health conditions, pregnancy, medication use, physical fitness and acclimatisation can all influence vulnerability.
The HSE identifies symptoms of heat stress that employers should be aware of, including:
- Excessive thirst
- Dizziness and headaches
- Muscle cramps
- Fatigue and inability to concentrate
- Heat exhaustion
- Heat stroke, which can be life-threatening if untreated
Heat-related illness can also increase the likelihood of workplace accidents. Reduced concentration, slower reaction times and fatigue can significantly raise safety risks, particularly in situations where the affected worker is operating machinery, driving or carrying out physically demanding tasks.
Special considerations for outdoor workers
Because of the nature of their jobs, construction, agriculture, utilities, highways maintenance, logistics and grounds maintenance workers often have limited opportunities to escape high temperatures.
If they have outdoor workers, employers should consider:
- Scheduling strenuous work during cooler morning or evening periods, if possible.
- Increasing the frequency of rest breaks.
- Encourage workers to remove PPE when resting. This will help the body to reduce heat/body temperature.
- Providing shaded rest areas.
- Provide sun protection cream, factor 50 if possible.
- Ensuring easy access to cool drinking water.
- Monitoring workers for signs of heat stress or heat stroke.
- Reviewing staffing levels and workloads during periods of extreme heat.
- Ensure workers can recognise the early symptoms of heat stress.
Risk assessments should also consider ultraviolet (UV) exposure and the cumulative effects of prolonged outdoor working during heatwaves.
Working in the sun
Too much sunlight can cause skin damage including sunburn, blistering and skin ageing. In the long term, it can lead to an increased risk of skin cancer.
Managing indoor workplaces
It is not just outdoor environments that present heat risks. Offices, warehouses, factories and healthcare settings can all be affected by uncomfortable and potentially unsafe temperatures. If employees are working near machinery, ovens, server rooms or in poorly ventilated buildings, they may face elevated risk levels.
Practical controls may include:
- Improving ventilation.
- Using fans or air-conditioning systems where appropriate.
- Installing blinds or reflective window films.
- Allowing for additional/extended rest breaks.
- Relocating workstations away from direct sunlight.
- Adjusting dress codes.
- Allowing flexible or remote working arrangements where feasible.
These measures support wellbeing and can help maintain productivity during periods of extreme heat.
PPE and vulnerable workers
A particularly important issue highlighted during the 2026 heat events was the effect of personal protective equipment (PPE) on heat stress. UKHSA and the HSE jointly warned that wearing PPE in hot conditions can significantly increase the risk of overheating because it restricts the body’s ability to cool itself effectively.
Employers should therefore assess how PPE requirements interact with heat risks and consider:
- More frequent rest breaks.
- Increased hydration opportunities.
- Additional staff rotations.
- Enhanced monitoring of workers wearing protective clothing.
Particular attention should also be given to workers who may be more vulnerable, including pregnant employees, older workers and individuals with pre-existing health conditions. Individual risk assessments may be required in some circumstances.
The future of heat risk management
From a once in a generation event, extreme heat events are now nearly an annual phenomenon and it is likely that the temperatures will continue to rise. Therefore, heatwave planning cannot just be a reactive process. The HSE has explicitly called on employers to prepare for increasingly frequent periods of extreme heat and to incorporate heat-related risks into normal health and safety management processes.
Forward-thinking employers are beginning to treat heat resilience in the same way they approach other foreseeable hazards, embedding it within risk management, business continuity and employee wellbeing strategies. Measures such as trigger-based heat action plans, supervisor training and clear employee communications can help organisations respond consistently when temperatures rise again – as they will.
