What temperature is legally too hot to work in the UK?

Tuesday 19 July saw a record temperature of 40.3C in the UK, and, with more frequent heatwaves expected due to climate change, extreme temperatures are something employers may now be forced to deal with.

Intense heat events and heat-related illnesses can be threatening – even fatal – to human health. According to the UK Health Security Agency (UKHSA), during a level 4 heat alert (as was issued this week), “illness and death may occur among the fit and healthy, and not just in high-risk groups”. Episodes of heat stroke, cardiovascular and respiratory disorders are all likely to increase during rising temperatures.

Currently, no law in the UK or Ireland states any temperature deemed too hot or cold to work. But, in the face of a climate emergency, two of the UK’s most powerful Unions are calling for change.

The GMB and the TUC have petitioned the government to set a maximum workplace temperature to protect workers. The TUC wants employees to stop working if indoor temperatures hit 30°C (or 27°C for strenuous jobs), whilst the GMB wants the maximum indoor temperature to be 25°C.

On 11 July 2022, 37 MPs signed an early day motion (EDM) which supported the same responsible temperatures as suggested by the TUC. Ian Mearns, the Labour MP for Gateshead, tabled the EDM in the House of Commons. The motion states:

“That this House notes that recent surveys of workplace health and safety representatives show that high temperatures are one of their top concerns.

“(It) regrets that workers in the UK have no guaranteed legal safeguards from working in uncomfortable high temperatures, and that the consequences of this range from dizziness, tiredness, asthma, throat infections and, in extreme cases, heat stroke and death.

“(It) insists that without recognised law, current recommendations for employers to maintain a reasonable temperature within the workplace are impossible to enforce unless a worker is seriously injured or killed from heat stress.

“And (it) calls on the Government to introduce legislative proposals to ensure a maximum working temperature of 30 degrees Celsius, or 27 degrees Celsius for those doing strenuous work, beyond which employers would have a statutory duty to introduce effective control measures, such as installing ventilation or moving staff away from windows and sources of heat.”

For now, and with no guarantee that the EDM will pass into law, employers must stick to health and safety work laws and ensure that existing working conditions are “reasonable”. While there are no meaningful maximum temperature limits (the HSE has previously suggested minimum temperature guidelines), according to the HSE, employers must monitor the wellbeing of their staff in warm weather and ensure that they have access to water.

There are difficulties when it comes to setting maximum temperature limits. Not least because heat is an issue all year round in some jobs (e.g., bakeries, foundries and smelting operations). Nevertheless, if employees complain about working in excessive heat, an employer should carry out a risk assessment and act on the results. Furthermore, if an employee has a disability, then under the Equality Act 2010, an employer may have to make “reasonable adjustments” when the temperature gets too hot.

For now, we would recommend all employers to be prudent, listen to the concerns of their employees, undertake risk assessments, and introduce measures designed to mitigate the risks and protect the health and wellbeing of their staff. Temporary measures such as relaxing any uniform policy, ensuring employees are not showing signs of heat exhaustion (especially vulnerable employees) and providing adequate hydration should be introduced as a minimum. For employees, we suggest they raise concerns with their employers and ask if they can work from home (if possible) if their workplace cannot maintain a reasonable temperature.