Working in Extreme Heat

Our Ref: HSR/1/14

Head Office Circular: NP/135/22

14th July 2022

To: The Secretary





Dear Colleague,


I write in relation to the high temperatures currently being experienced in many parts of the country.  As temperatures soar the UK Health Security Agency (UKHSA) has issued a heat-health alert:

The Met Office at has extended an Amber Extreme heat warning, as temperatures look to build later this week and early next week for much of England and Wales.


The Amber warning, which has been issued for Sunday (17th July) and Monday (18th July), highlights likely adverse health effects for the public - not just limited to those most vulnerable to extreme heat. Temperatures could be in excess of 35°Celsius in the southeast of England, and more widely around 32°C within the warning area. These high temperatures could extend further into next week and an extension of the warning will be considered in the coming days.  

The UKHSA top ways for staying safe are to:

·       look out for those who may struggle to keep themselves cool and hydrated – older people, those with underlying conditions and those who live alone are particularly at risk

·       stay cool indoors by closing curtains on rooms that face the sun – and remember that it may be cooler outdoors than indoors

·       drink plenty of fluids and avoid excess alcohol

·       never leave anyone in a closed, parked vehicle, especially infants, young children or animals

·       check that fridges, freezers and fans are working properly

·       try to keep out of the sun between 11am to 3pm, when the UV rays are strongest

·       walk in the shade, apply sunscreen and wear a wide-brimmed hat, if you have to go out in the heat

·       avoid physical exertion in the hottest parts of the day

·       make sure you take water with you if you are travelling

·       take care and make sure to follow local safety advice if you are going into the water to cool down


Read the UKHSA COVID-19 and summer temperatures blog for advice on how to stay well in hot weather.


While the UKHSA advice is more focused on the home environment, it also has implications for workers. It is a scandal that here is no maximum workplace temperature for workers in this country (although one exists for the transport of livestock). RMT has for many years been campaigning for maximum workplace temperatures, along with the TUC, demanding a change in the law so that employers must attempt to reduce temperatures if they get above 24°C and workers feel uncomfortable. Employers should be obliged to provide sun protection and water. We also want ministers to introduce a new absolute maximum indoor temperature, set at 30°C (or 27°C for those doing strenuous jobs), to indicate when work should stop. Working in hot weather can lead to dehydration, muscle cramps, rashes, fainting, and – in the most extreme cases – loss of consciousness and death. Outdoor workers are three times more likely to develop skin cancer.  


For more information see TUC learning tool, Too hot, too cold - Too hot, too cold. Also  Sign the petition for a maximum working temperature.

There are a number of control measures that can sensibly be introduced into the workplace including:


  • regulating the amount of time spent working in hot conditions
  • providing a plentiful supply of clean, cool drinking water
  • providing mechanical aids to reduce the work rate
  • relaxing the dress/uniform code and monitoring the health of workers especially those who may be more susceptible to the risk of heat stress
  • changing working practices 
  • supplying sun screen to those who job exposes them to direct sunlight 
  • taking breaks in cool locations
  • providing canopies/shade were possible  


Keeping workplace buildings cool: workplaces can be kept cooler and more bearable by taking simple steps such as opening windows, using fans, moving staff away from windows or sources of heat. 


Climate-proofing workplaces: buildings can be prepared for increasingly hot weather by installing ventilation, air-cooling and energy efficiency measures. 


Employers should have a policy to deal with hot weather and have carried out a risk assessment of the risks of hot weather in consultation with RMT Safety Reps. 


Other useful information can be found on the HSE website at:


Please bring the contents of this circular to the attention of relevant members. 


Yours sincerely



Michael Lynch

General Secretary