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Carbon monoxide (CO)

If you think you may have CO poisoning

  • Switch off any appliances that may be causing the problem and open the windows
  • Do not use appliances until they are checked by a properly qualified engineer
  • See your GP or local A&E

Carbon monoxide (CO) is a colourless, odourless gas and is very poisonous. It is produced when we burn wood, oil, coal, gas and charcoal for heating and cooking. CO is also produced by faulty or poorly serviced appliances.

CO poisoning symptoms

  • The symptoms of CO poisoning include: headache, nausea, vertigo/dizziness, breathlessness, weakness, chest pain and unconsciousness,
  • Being exposed to low levels of CO for a long time can also cause serious health problems.
  • Do not ignore the symptoms of CO poisoning especially when;
    • people in the same place have similar symptoms,
    • you have recently moved in,
    • you have had a new appliance fitted, like a boiler or wood burner,
    • you have had building work done,
    • you feel better when you are outside,
    • you have recently switched on the heating.

CO at home

At home, properly serviced and maintained appliances have a low risk of CO poisoning. But, appliances that are faulty, badly installed or poorly maintained, may produce CO.

Avoid CO poisoning at home by:

  • Making sure that all fuel-burning appliances (for example, boilers, wood burners) are serviced once a year by  a properly qualified engineer,
  • Having chimneys and flues swept once a year.

CO on holiday

When you are on holiday, having a day out, camping or on a boat, remember that portable barbeques, stoves, heaters and generators can all produce CO.

Avoid CO poisoning on holiday by:

  • Taking a CO alarm with you and using it
  • Never taking a portable barbeque indoors or into a tent or caravan
  • Never using a generator indoors

CO alarms

CO alarms make a noise if there are dangerous levels of CO in a place

  • Only use an alarm that is clearly labelled with BS EN 50291.
  • An alarm is only a back-up. Appliances still need to be properly installed, maintained and regularly tested.

What should I do if I am a member of the public

Remember that preventing CO poisoning is easy:-

  1. Signs – the main symptoms of CO poisoning are; headaches, dizziness, nausea, breathlessness, collapse and loss of consciousness.
  2. Service – make sure all fuel-burning appliances are serviced once a year by a properly qualified engineer.
  3. Sound – use an alarm that will sound if CO levels rise  – this could save your life.

What should I do if I am a healthcare professional

  • When patients arrive at the ED with a headache, especially after midnight or early in the morning, consider CO poisoning
  • Public Health Wales has developed an algorithm to help medical professionals assess the possibility of CO poisoning in their patients and work out what action to take.

If your patient has CO poisoning, inform the Environmental Public Health team at Public Health Wales.

More information

For more information on properly qualified engineers contact:

For Gas: Gas Safe Register tel. 0800 408 5500
For Oil: OFTEC tel. 0845 658 5080
For Solid Fuel: HETAS tel. 0845 634 5626

If you think you have been exposed to CO contact the gas Emergency Line on 0800 111999.