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What should I do if I think I have carbon monoxide poisoning?

Carbon monoxide (CO) is an invisible, odourless and colourless toxic gas that can poison and eventually kill people without them realising it. It’s often caused by faulty or badly serviced gas and other fossil fuel-burning appliances or systems. Poisoning can happen in a matter of minutes and is responsible for more deaths than any other poison.

How to protect yourself from carbon monoxide poisoning


Buy a carbon monoxide detector for your home or office. They’re available from most DIY stores. You should also make sure you have any gas or fossil-fuel burning appliances serviced regularly.

There’s more information on our gas safety booklet.


If you think you might have carbon monoxide poisoning


If you think you’ve been exposed to carbon monoxide (CO) you should get medical help as soon as you can.

For low-level CO poisoning

See your GP as soon as you can. Symptoms of low-level poisoning include:

  • a tension-type headache
  • dizziness
  • nausea and vomiting
  • tiredness and confusion
  • stomach pain
  • shortness of breath and difficulty breathing

These symptoms can be hard to spot as they’re similar to other illnesses like food poisoning or flu. It’s worth remembering that CO poisoning doesn’t cause a raised temperature or fever. And the symptoms will get better when you’re away from the source of the CO, and worse the more you’re exposed to it.

For high-level CO poisoning

Go to your local accident and emergency (A&E) department immediately.

If you’ve been breathing in high levels of CO gas your symptoms might include:

  • an impaired mental state and personality changes
  • vertigo - the feeling that you or the environment around you is spinning
  • ataxia - a loss of physical coordination caused by underlying damage to the brain and nervous system
  • breathlessness and tachycardia (a heart rate of more than 100 beats per minute)
  • chest pain caused by angina or a heart attack
  • seizures - an uncontrollable burst of electrical activity in the brain that causes muscle spasms
  • loss of consciousness - in cases where there are very high levels of CO, death can occur within minutes.


If you think you might have a CO leak


Call the National Grid Gas Emergency Service immediately on 0800 111 999.


Reducing the risk

Make sure you get appliances like gas heaters, cookers, boilers and chimneys serviced regularly. You can also buy carbon monoxide alarms from most DIY stores.