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Carbon monoxide advice

Carbon monoxide (CO) is the most common form of household poison. You can't see it, taste it or smell it. CO poisoning can be fatal or cause permanent damage to your health.

Causes of carbon monoxide poisoning

Poisoning occurs when any fuel burning appliance has not been properly installed, maintained or is poorly ventilated. Sources can include boilers, gas fires, central heating systems, water heaters, cookers and open fires.

If the fuel in these appliances does not burn fully, carbon monoxide (CO) gas is produced.

The build-up of carbon monoxide can also be as a result of any of the following:

  • Indoor use of a barbecue grill or outdoor heater
  • Using cooking appliances for heating purposes
  • Enclosed or unventilated spaces - burning fuel in an enclosed or unventilated space, where there are no air vents, windows or doors left open or ajar
  • Faulty or damaged appliances - heating or cooking
  • Heating appliance not maintained or serviced
  • Badly ventilated rooms - sealed windows, no air bricks
  • Blocked chimneys or flues - birds nests, fallen bricks, growing vegetation, bad DIY
  • Poor or improper installation or use of appliances - such as cooking and heating devices
  • Running engines such as cars or lawnmowers in garages
  • Old appliances that have not been serviced or looked after properly
  • Paint fumes - fumes from cleaning fluids and paint removers that contain methylene chloride (dichloromethane) can also cause CO poisoning

Top tips for prevention

  • Ensure regular servicing of your fuel appliances.
  • Installation, repair and regular servicing of any gas appliances should be done by a Gas Safe registered engineer
  • Do not leave petrol fuelled lawn mowers or cars running in the garage
  • Make sure you have good ventilation and enough fresh air in the room containing your fuel appliance
  • Ensure chimneys/flues aren’t blocked and vents aren’t covered
  • Get your chimney swept from top to bottom at least once a year by a qualified sweep.
  • Do not use barbecues in enclosed spaces, i.e. indoors or inside a tent or caravan.

Carbon monoxide alarms

Carbon monoxide alarms are a useful but only as a back-up precaution. They aren’t a substitute for proper installation and maintenance of fuel burning appliances.

Make sure the alarm meets British Standard EN50291 and ideally the British Standard Kitemark. You should install, check and service CO alarms according to the manufacturer's instructions.

CO alarms are available from DIY and hardware stores.

Look out for the danger signs

  • Yellow or orange rather than blue flames (except fuel effect fires or flueless appliances which display this colour flame)
  • Soot or yellow/brown staining around appliances or fireplaces.
  • Pilot lights that frequently blow out
  • Increased condensation inside windows.

The symptoms

The early symptoms of poisoning can be easily confused with many common ailments and can develop quickly or over a number of days or months. Look out for

  • A headache - this is the most common symptom
  • Feeling sick and dizzy
  • Feeling tired and confused
  • Being sick and having stomach pain
  • Shortness of breath and difficulty breathing.

Take action

If you think you have carbon monoxide poisoning, you should:

  • Leave the contaminated area immediately and get out in to the open air
  • Seek urgent medical advice from either your GP or your Accident and Emergency department.
  • Open the windows and doors to ventilate the room, and don’t sleep in it
  • Switch off all your gas appliances and don’t use them again until the problem has been fixed
  • Shut off the gas supply at the meter control valve - if gas continues to escape, call the Gas Emergency Free phone Number on 0800 111 999 
  • Call a Gas Safe registered engineer to check all your gas appliances.

Useful information

Gas safe register

To check if an engineer is on the register visit

Contact us

For more information please contact us on:

01392 872200


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