Carbon monoxide (CO) is a invisible gas with no smell, taste, or colour. It is produced when fuel-burning appliances, such as boilers, gas fires, wood burners, oil heaters, or cookers are incorrectly installed, poorly maintained, or insufficiently ventilated.
Every year in the UK, around 200 people are hospitalised with carbon monoxide poisoning. Because CO cannot be detected by human senses, taking preventive measures and installing working alarms is vital.
Recognising the Symptoms of CO Poisoning
Carbon monoxide poisoning can easily be mistaken for flu, food poisoning, or general fatigue. The six key symptoms to watch for are:
- Headaches
- Dizziness and light headedness
- Nausea and vomiting
- Breathlessness
- Fainting or collapse
- Loss of consciousness
Key Indicator: If your symptoms lessen or disappear when you leave the home and return when you go back inside, carbon monoxide exposure is a strong possibility.
Danger Signs on Fuel-Burning Appliances
Routinely inspect gas, oil, and solid-fuel appliances for physical warning signs of incomplete combustion:
- Pilot Lights: Burner or pilot flames that burn floppy orange or yellow instead of a crisp blue.
- Sooty Stains: Black or dark brown staining around or above boilers, fires, or flues.
- Excess Condensation: Heavy condensation forming on windows or walls in the room where an appliance is installed.
- Sluggish Fires: Coal or wood fires that burn sluggishly, go out repeatedly, or smoke back into the room.
If you spot any of these warning signs, turn off the appliance immediately and have it inspected by a qualified, registered engineer.
Recommended Safety & Maintenance Actions
- Fit CO Alarms: Install a carbon monoxide alarm compliant with BS EN 50291 in every room containing a fuel-burning appliance. Test alarms monthly and replace batteries or units according to the manufacturer’s guidance.
- Annual Servicing: Ensure boilers, gas fires, and oil heaters are serviced annually. Always hire a Gas Safe Register engineer for gas appliances or an accredited specialist for oil and solid fuel.
- Keep Vents Clear: Ensure air bricks, flues, and vents remain clear and unblocked at all times to allow dangerous gases to escape.
- Chimney Sweeping: Have chimneys and flues swept regularly by a qualified chimney sweep to prevent blockages.
- Safe Ash Disposal: Allow cooling ash from solid fuel fires to cool completely before disposing of it outdoors in a metal container or well clear of combustible waste.
Critical Precautions
- Never Use Outdoor Equipment Indoors: Never operate barbecues, charcoal grills, or camping gas stoves inside a house, garage, tent, or caravan. Smouldering charcoal produces lethal amounts of CO.
- Do Not Block Ventilation: Never seal or block air bricks, window vents, or extractor grilles in rooms with boilers or open fires.
- Never Ignore Faults: Do not continue using an appliance that trips out, shows orange flames, or leaves soot marks until a professional inspection is complete.
Emergency Actions & Essential Contacts
If You Suspect Carbon Monoxide Exposure or a Gas Leak:
- Open all doors and windows immediately to ventilate the property.
- Turn off gas appliances at the mains meter if it is safe to do so.
- Evacuate the building and get everyone into fresh air.
- Seek urgent medical help: Call 111 or go to A&E immediately if anyone exhibits symptoms.
- Call the Gas Emergency Helpline: Dial 0800 111 999 for immediate assistance.