Carbon monoxide is an odourless, colourless, tasteless, and poisonous gas and is formed by the incomplete combustion of carbon-containing fuels, such as gas (mains or LPG), coal, oil, coke and wood. Gas fires, stoves, heating boilers, gas-powered water heaters, paraffin heaters and solid fuel-powered water heaters are all potential sources of CO.

How is Carbon Monoxide (CO) produced:

• If an appliance isn’t working correctly or properly installed
• If it hasn’t been properly maintained or regularly serviced
• If the chimney or flue, or purpose-provided vents are blocked 

You may detect it thanks to the activation of a carbon monoxide alarm installed at the premises.  Or, in some cases, it can be spotted when people at the location start showing symptoms of CO poisoning.

What are the signs that a gas appliance may not be working correctly?

The signs may include:

• Lazy yellow flames instead of defined blue ones
• Yellow or brown staining on, or around the appliance
• Soot deposits on, or around the appliance
• Unusual or unexpected sounds around the appliance
• Increased condensation inside windows
• The activation of the audible CO alarm

What are the symptoms of CO poisoning?

• Headaches 
• Dizziness 
• Nausea and vomiting 
• Tiredness and confusion 
• Stomach, chest or muscle pain 
• Shortness of breath or difficulty breathing
• Loss of consciousness 

The symptoms are similar to flu or food poisoning and may get worse when the person spends more time in the affected area, or better when you leave and go outside.