What is CO poisoning?

Carbon monoxide (CO) is a poisonous gas that has no smell or taste. Breathing it in can make you unwell, and it can kill if you're exposed to high levels.

After CO is breathed in, it enters your bloodstream and mixes with haemoglobin (the part of red blood cells that carry oxygen around your body) to form carboxyhemoglobin.

When this happens, the blood is no longer able to carry oxygen, and this lack of oxygen causes the body's cells and tissue to fail and die.

What are the symptoms?

The symptoms of carbon monoxide (CO) poisoning are flu like. However, unlike flu, CO poisoning does not cause a high temperature.

A headache is the most common symptom of mild CO poisoning.

Other symptoms include:

  • dizziness
  • feeling and being sick
  • tiredness and confusion
  • stomach pain
  • shortness of breath and difficulty breathing

The symptoms of carbon monoxide poisoning are not always obvious, particularly during low-level exposure.

What are the causes?

Carbon monoxide (CO) is released when a fuel, such as gas, oil, coal and wood, does not burn fully. Household appliances, such as gas fires, boilers, central heating systems, water heaters, cookers, and open fires, may be possible sources of CO gas.

Running a car engine in an enclosed space can also cause CO poisoning.

CO leaks can happen when an appliance has been incorrectly fitted, badly repaired or poorly maintained. It can also occur if flues, chimneys or vents are blocked.

What should you do about it?

If you suspect you have been exposed to carbon monoxide, get fresh air immediately. Open doors and windows, turn off gas appliances and leave the house. See your doctor or go to your local A&E straight away.

A blood test or breath test will confirm the amount of carboxyhemoglobin in your blood. Medical professionals can advise if you need treatment for CO poisoning.

How do you prevent CO poisoning?

Get your appliances checked regularly and get an audible CO alarm fitted.

Gas Safe Register

Gas Safe Register operate the official UK list of gas businesses and qualified gas engineers that work for those businesses, as required by law, to ensure only those qualified engineers are licensed to legally work on gas.


If you have concerns about an appliance, and you need to find a qualified engineer to carry out an inspection to check any appliances you think may be faulty, you can get in touch with Gas Safe Register.

For general enquiries call: 0800 408 5500

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NHS

If you suspect that you are suffering from the symptoms of CO poisoning, you can visit the NHS website for more information. They can advise what action to take and the treatment that is usually provided.


Your symptoms may be less severe when you're away from the source of the carbon monoxide (CO).

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Gas emergency contacts

If you think there is an immediate danger, call the free 24-hour Gas Emergency Helpline on 0800 111 999 (GB) or the relevant service for your area (see below).

England, Wales and Scotland
0800 111 999


Northern Ireland
0800 002 001


Isle of Man
0808 1624 444


Guernsey
01481 749 000


Jersey
01534 755 555

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