Carbon Monoxide

What is Carbon Monoxide?

monoxide Carbon Monoxide (CO) is an invisible, odourless, tasteless & extremely toxic gas. CO is a result of incomplete combustion of fossil-fuels such as natural gas, bottled gas, solid fuels (wood, coal etc.). CO is absorbed by the red blood cells in the lungs in preference to oxygen, resulting in oxygen starvation & rapid damage to the heart & brain.


Here are a few U.K. statistics which may set alarm bells ringing...

• 23 deaths from Carbon Monoxide poisoning in 2009/2010 •

176 near misses from Carbon Monoxide poisoning in 2009/2010

• 72% of Gas Safe (formally CORGI) registered engineers discovered a Carbon Monoxide leak when performing routine services on appliances

• 40% of recorded Carbon Monoxide incidents were caused by bad installation and repair of appliances.

However, incidents of Carbon Monoxide poisoning are often unrecorded as they can easily be misdiagnosed – low level exposure to Carbon Monoxide results in symptoms similar to flu. Due to this the actual number of poisoning incidents is almost certainly much higher than the figures shown above.

CO is produced by any fossil-fuel burning appliances such as gas or oil boilers/furnaces, gas/solid fuel fireplaces, gas appliances, solid fuel stoves etc. Heavy doses of CO will cause a person to collapse & die within minutes [see adjoining table]. Lesser doses of CO may cause flue-like symptoms, headaches, drowsiness, fatigue, nausea, vomiting

Sources of Carbon Monoxide

If a home has any of these appliances it is a potential source of Carbon Monoxide


Toxic amounts of CO can be produced if there is:

An appliance not working correctly due to poor installation, lack of servicing or blocked chimney or flue, Inadequate ventilation, resulting in insufficient oxygen for the fuel to burn properly or a cracked chimney or flue.

Avoiding Carbon Monoxide Poisoning

• Ensure your appliances are correctly installed and SERVICED ANNUALLY

• Ensure that rooms in your home containing heating appliances are properly ventilated - NEVER BLOCK VENTS • Make sure all chimneys are regularly swept and kept clear

• Use appliances only for the PURPOSE for which they were designed, e.g. do not use a cooker to heat a room

• NEVER use any appliance if you suspect it might be faulty

• If undertaking ALTERATIONS to your home which may affect the safety or efficiency of your heating installation (e.g. adding an extension, converting a garage, removing internal walls, changing a living room into a bedroom, double glazing / weather sealed doors) follow this safety advice:

• Do not block or build around any existing air vents or flues • If creating a new living space, ensure it has ventilation in accordance with Building Regulations

• If adding additional radiators ensure that your boiler can cope with the additional capacity • If you are altering or adding appliances to a natural gas or LPG installation, ensure that work is carried out to IS813:2002 Domestic Gas Installations

• Get professional advice on ventilation and flueing before embarking on alterations to your house. Contact your fuel supplier for details of qualified personnel

• Use Carbon Monoxide alarms but remember these are no substitute for regular inspection and maintenance of appliances, vents, flues and chimneys.

Check that the Carbon Monoxide alarm complies with the EN 50291 standard.

For more information regarding Carbon Monoxide please go to: