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Gas and carbon monoxide leaks

If you smell gas or you think there has been an escape of other fumes such as carbon monoxide, call the free 24 hour national emergency number on 0800 111 999, straight away.

Gas distributors are responsible for dealing with leaks and emergencies within their networks. A leak of gas or carbon monoxide can be very dangerous. This page explains what to do if you think there's a gas or carbon monoxide leak.

If you smell gas

If you suspect a gas leak, act straight away:

  • call the emergency number on 0800 111 999
  • never use your mobile phone in your home if you suspect a gas leak. If you need to use a mobile phone for the emergency call, go outside or to a neighbour’s house
  • open your doors and windows
  • do not use matches or any other naked flames
  • do not smoke
  • do not turn any electrical switches on or off – including light switches and doorbells
  • make sure that the gas supply to an appliance has not been left on or that the pilot light on your boiler has not gone out
  • turn off the gas supply at the meter, if you know how to.

Fixing the leak

Gas distributors are responsible for dealing with gas leaks and emergencies in their area. When you report a leak they will come to your home free of charge.

Top tips

Protection from carbon monoxide poisoning

To protect yourself against carbon monoxide poisoning:

  • get your gas appliances serviced and maintained regularly
  • check chimneys and flues regularly
  • use a carbon monoxide detector. This alerts you to carbon monoxide by changing colour or beeping.

If you have an electrical detector, ensure you check the batteries regularly.

If the leak is in your home

If the leak is in your home, they may make it safe by turning off the supply. If the engineer can fix the leak quickly, they will. If not, they will isolate the appliance to prevent unsafe use and turn the gas back on, if it is safe to do so.

The engineer will leave you information about who to contact to have the appliance repaired.

If the disruption of the supply to your property has been caused by the distribution company, you will be entitled to compensation if you are without gas for more than 24 hours. You should contact your supplier if this applies to you.

How can you tell if there's a carbon monoxide leak?

Carbon monoxide is produced when gas does not burn properly. It is very dangerous to your health as it can reduce your blood’s ability to transport oxygen around your body. It can be difficult to detect as it is invisible and has no smell or taste, but signs of a possible carbon monoxide leak include:

  • your boiler pilot light frequently dies out
  • gas flames on appliances such as cookers are yellow or orange instead of blue
  • you can see soot or a scorched appearance on gas appliances
  • there is excessive condensation on your windows.

What to do if you think there's a carbon monoxide leak?

If you think there is a carbon monoxide leak in your home, you should:

  • get out of the property immediately
  • contact the national emergency line on 0800 111 999 straight away
  • if anyone affected feels sick or has a headache, get urgent medical attention from your GP or A&E department – they may have been poisoned
  • switch off appliances and do not use them until they've been checked
  • make sure any repairs are carried out by a Gas Safe registered engineer.


All gas engineers must be on the new Gas Safe Register to do gas work lawfully. Always ask for a Gas Safe registered engineer and always ask to see their ID card.

Next steps

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