Carbon monoxide

Carbon monoxide poisoning - what are the symptoms?

You can't see it, taste it or smell it but it can kill quickly and with no warning. Unsafe gas appliances produce a highly poisonous gas called carbon monoxide (CO). It can cause death as well as serious long term health problems such as brain damage.

Remember the six main symptoms to look out for:

Student signs
  1. Headaches
  2. Nausea
  3. Breathlessness
  4. Collapse
  5. Dizziness
  6. Loss of consciousness

Being aware of the symptoms could save your life.

Carbon monoxide symptoms are similar to flu, food poisoning, viral infections and simply tiredness. That's why it's quite common for people to mistake this very dangerous poisoning for something else.

Other signs that could point to carbon monoxide poisoning:

  • Your symptoms only occur when you are at home
  • Your symptoms disappear or get better when you leave home and come back when you return
  • Others in your household are experiencing symptoms (including your pets) and they appear at a similar time

What should I do if I experience any symptoms of carbon monoxide poisoning?

  • Get fresh air immediately. Open doors and windows, turn off gas appliances and leave the house
  • See your doctor immediately or go to hospital - let them know that you suspect carbon monoxide poisoning. They can do a blood or breath test to check
  • If you think there is immediate danger, call the Gas Emergency Helpline
    • Great Britain: 0800 111 999
    • Guernsey: 01481 749000
    • Isle of Man: 0808 1624 444
    • Northern Ireland: 0800 002 001
  • Get a Gas Safe registered engineer to inspect your gas appliances and flues to see if there is a dangerous problem

Don't assume your gas appliances are safe: get a Gas Safe registered gas engineer to do a check. This is the only safe way to prevent yourself and those around you from incurring serious illness or death due to carbon monoxide exposure.

What is carbon monoxide?

Carbon monoxide (CO) is a highly poisonous substance produced by the incomplete burning of gas and Liquid Petroleum Gas (LPG).

This happens when a gas appliance has been incorrectly fitted, badly repaired or poorly maintained. It can also occur if flues, chimneys or vents are blocked.

Oil and solid fuels such as coal, wood, petrol and oil can also produce carbon monoxide.

What is carbon monoxide poisoning?

  • Carbon monoxide poisoning occurs when you breathe in even small amounts of the gas.
  • When you breathe in carbon monoxide, it gets into your blood stream and prevents your red blood cells from carrying oxygen. Without oxygen, your body tissue and cells die.
  • Levels that do not kill can cause serious harm to health when breathed in over a long period of time. Long term effects of carbon monoxide poisoning include paralysis and brain damage. Such long term effects occur because many people are unaware of unsafe gas appliances and subsequent gas leaks.
Gas cooker

How do I avoid a carbon monoxide leak in my home?

Your home may show signs of carbon monoxide. Any one of the following could be a sign that there is carbon monoxide in your home. Get your gas appliances checked to avoid carbon monoxide poisoning.

  • The flame on your cooker, fire or boiler should be crisp and blue. Lazy yellow or orange flames mean you need to get your appliances checked
  • Soot or dark staining around or on appliances
  • Pilot lights that frequently blow out
  • Increased condensation inside windows

If you have a faulty appliance in your home, it could lead to carbon monoxide poisoning. Get it checked as soon as possible by a Gas Safe registered engineer.

Why should I get a carbon monoxide alarm?

Because carbon monoxide has no taste, smell or colour, Gas Safe Register strongly recommends you fit an audible carbon monoxide alarm in your home.

While an alarm will alert you to carbon monoxide in your home, it is no substitute for using a Gas Safe registered engineer.

A carbon monoxide alarm looks similar to a smoke alarm and is very easy to fit by following the manufacturer's instructions. You can purchase a carbon monoxide alarm for around £10 at your local DIY store, supermarket or from your energy supplier.

Before purchasing a carbon monoxide alarm, always make sure it is officially approved to BS:EN50291:2001 or BS:EN50291:2010. It must have a British or European approval mark on it, such as a Kitemark.

You are particularly at risk from carbon monoxide poisoning while sleeping, as you may not be aware of early carbon monoxide symptoms until it's too late. Do not use the ‘black spot' detectors that change colour when carbon monoxide is present. These will not make a sound to wake you up if the poisonous gas is present while you are sleeping.

Further information about Gas Safety and how to find a registered gas engineer can be found at the following websites: