Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal. Carbon-based fuels are safe to use. It is only when the fuel does not burn properly that excess CO is produced, which is poisonous. When CO enters the body, it prevents the blood from bringing oxygen to cells, tissues, and organs.
You can't see it, taste it or smell it but CO can kill quickly without warning. According to the HSE, every year around 7 people die from CO poisoning caused by gas appliances and flues that have not been properly installed, maintained or that are poorly ventilated. Levels that do not kill can cause serious harm to health if breathed in over a long period. In extreme cases paralysis and brain damage can be caused as a result of prolonged exposure to CO. Increasing public understanding of the risks of CO poisoning and taking sensible precautions could dramatically reduce this risk.
There are signs that you can look out for which indicate incomplete combustion is occurring and may result in the production of CO:
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 or on appliances
pilot lights that frequently blow out
increased condensation inside windows
There are a number of simple steps that gas consumers can take to keep themselves safe.
Carbon monoxide can be produced by any combustion appliance, including those that burn fossil fuels e.g. oil, wood and coal. If you have one of these appliances you should make sure that it is serviced and maintained by a competent person and the chimney is regularly swept.