Carbon monoxide alarms and emergencies

What is carbon monoxide?

Carbon monoxide (CO) is a poisonous gas that you can’t see, taste or smell. It’s made when carbon-based fuels, like gas, oil, wood and coal don’t burn properly, which is why it’s really important to make sure your appliances are fitted in the right way - and checked regularly.

Carbon monoxide poisoning caused by faulty or badly fitted or maintained appliances can lead to serious health problems and kills around 15 people a year in the UK.

How to stay safe

Gas, oil, wood and coal are all safe to use, it’s faulty or badly fitted or maintained appliances that put you at risk of carbon monoxide poisoning.

Gas appliances should be fitted and checked by a Gas Safe™ registered engineer. You can find one here.

Our gas engineers are all Gas Safe™ registered and cover most areas of the UK. Call us on 0800 051 1470 to find out more.

Non-gas appliances that use oil, wood or coal should be fitted and checked by an OFTEC or HETAS approved engineer. 

We recommend that you get your appliances checked every year.

Carbon monoxide detectors

Fitting a detector that will let you know straight away if there’s a carbon monoxide leak in your home is a good extra precaution, but it shouldn’t be done in place of having your appliance(s) fitted and checked by an approved engineer. 

How to choose the right one

Your carbon monoxide detector should have:

  • an audible alarm that will wake you up, you’re most at risk from carbon monoxide poisoning when you’re asleep.
  • a British Standard EN 50291 mark also written as BSEN 50291 or shown with the CE mark.
  • a British or European Kitemark and a testing approval mark like the Loss Prevention Certification Board (LPCB) mark. 

Free gas safety checks available

If you’re on a means-tested benefit you may qualify for a free gas safety check, which would spot any problems in your home. Call us on 0345 059 9905 to find out more.

How do I know if I’m at risk of carbon monoxide poisoning?

You’re at risk of carbon monoxide poisoning if:

  • your appliance wasn't fitted properly.
  • or it’s not working as it should be.
  • there’s not enough fresh air in the room.
  • your chimney or flue gets blocked up.
  • you let non-Gas Safe™ registered engineers fit or maintain your gas appliance(s).
  • or non-OFTEC/HETAS approved engineers if your appliance uses oil, wood or coal.

What are the signs of a carbon monoxide leak?

Even though you can’t see, taste or smell carbon monoxide there are signs you can look out for.

Remember, it’s not just faulty or badly fitted or maintained gas fires and boilers that can have carbon monoxide leaks, it’s any appliance that uses a carbon-based or fossil fuel, including oil, wood and coal.


Tell-tale signs of a carbon monoxide leak include:

  • yellow or brown stains on, or near, an appliance.
  • a pilot light that keeps going out .
  • more condensation than normal on the inside of windows.
  • a yellow flame instead of a blue one (apart from flueless fires).

What to do if you think you’ve got a carbon monoxide leak

  • Switch off the appliance and don’t use it again until an approved engineer has checked it.
  • Open all your doors and windows and go outside to get some fresh air. 
  • Tell your GP even if you don’t feel unwell and ask for either a blood or breath test to check for carbon monoxide poisoning.
  • If someone feels unwell take them outside in the fresh air straight away and call 999 or go to your nearest Accident and Emergency department (A&E). 
  • Don’t smoke, turn lights on or off, or do anything else that could cause a spark.

For emergency help with gas call 0800 111 999.

For gas safety advice call the Health and Safety Executive (HSE) on 0800 300 363. The HSE is the national independent watchdog for health, safety and illness.

If you get a means-tested benefit you may qualify for a free gas safety check, which would spot any problems in your home. Call us on 0345 059 9905 to find out more.

What are the symptoms of carbon monoxide poisoning?

Symptoms can be very similar to many common illnesses like flu or food poisoning, so make sure you tell your GP if you think it could be carbon monoxide poisoning and ask for a blood or breath test to check.

Common symptoms can include:

  • headaches.
  • dizziness. 
  • feeling or being sick. 
  • tiredness or drowsiness. 
  • stomach pain.
  • difficulty breathing.

The longer you breath in carbon monoxide, the worse your symptoms will get. Severe symptoms can include:

  • confusion.
  • memory loss.
  • co-ordination problems. 
  • personality changes or unusual behaviour. 
  • tachycardia (a heart rate of more than 100 beats a minute). 
  • chest pain caused by angina or a heart attack.
  • seizures or muscle spasms.
  • loss of consciousness.

Very high levels of carbon monoxide can kill within minutes, but sometimes symptoms can develop weeks or months after you’ve breathed it in.

Babies, young children, pregnant women and people with heart or breathing problems may be affected by carbon monoxide more quickly than others.

Pets

Pets are affected by carbon monoxide poisoning too. If your pet becomes ill or dies suddenly, and there’s no obvious reason for it, it could be the first sign of a carbon monoxide leak. Let your vet know if your pet becomes unwell and you think it could be caused by carbon monoxide poisoning.

What to do if you think a gas appliance is unsafe

  • If you think a gas appliance isn’t working properly, stop using it and call a Gas Safe™ registered engineer for help. 
  • They’ll give the appliance a gas safety check and if it fails they’ll stick a red warning notice on it. It’s against the law for anyone except a Gas Safe™ registered engineer to remove a red warning notice. 
  • The engineer will tell you if your appliance can be repaired or if it needs replacing.

You can find out more on gassaferegister.co.uk – the official list of gas engineers that are qualified to work safely and legally on gas appliances. Always check your engineer is on the Gas Safe™ register.

Our gas engineers are all Gas Safe™ registered and cover most areas of the UK. Call us on 0800 051 1470 to find out more.

What to do if you think an oil, wood or coal appliance is unsafe

  • Stop using the appliance and call an approved engineer for help. They’ll let you know if it can be repaired or if it needs replacing and when it’s safe to use. 
  • If you have a solid fuel appliance which uses wood or coal for instance you can find an approved engineer at hetas.co.uk.
  • The Heating Equipment Testing and Approval Scheme (HETAS) is a government-recognised body that approves biomass and solid fuel domestic heating appliances, fuels and services and registers approved engineers. 
  • If you have an appliance that uses oil you can find an approved engineer at oftec.org.
  • The Oil Firing Technical Association represents the oil heating and cooking industry in the UK and the Republic of Ireland and registers approved engineers.