Carbon monoxide (CO) is very dangerous and is often referred to as the “silent killer” as it has no colour, taste or odour, which makes it difficult to detect.  Even the symptoms are misleading and you may think that you are coming down with the flu. Because it is very difficult to detect, there are steps that you can take which may end up saving you and your loved ones lives. Carbon monoxide poisoning may occur when gas appliances such as boilers, ovens, free standing cookers or gas fireplaces aren't burning their fuel properly which may be caused from bad installation or in the case of gas fireplaces, the chimney flue becomes blocked.  Not only is it gas appliances that can cause CO, but any product that burns oil or solid fuel (coal, wood, petrol). If you notice that you or those around you are getting flu like symptoms which seem to come and go, it is best to that this checked out by your GP.  Even animals are able to get CO poisoning, so if you have any pet, keep an eye on them. Some signs to look out for at moderate levels are; dizziness, headache, nausea, some people even faint.  Low level poisoning may cause mild headaches, mild nausea and may have longer term effects on your health.  As stated before, some of these symptoms are similar with flu symptoms but as always, if in doubt go to your GP.  As well as going to your GP and telling them that you suspect carbon monoxide poisoning, open your windows in order for fresh air to come in, turn off all combustion appliances and leave your house. It is wise to have a CO detector installed in your home.  There are numerous ones available today and authorities have stated that these are just as important as having smoke alarms.  When choosing a CO detector, choose one that makes noise should the presence of CO be detected.  What is a CO detector?  This is a device that detects the presence of carbon monoxide gas.  These are inexpensive and can be bought from most plumbers merchants. Early designs were basically a white pad which would fade to a brownish or blackish colour if carbon monoxide was present. Such chemical detectors were cheap and were widely available, but only give a visual warning of a problem. As carbon monoxide related deaths increased during the 1990s, audible alarms became standard. The alarm points on carbon monoxide detectors are not a simple alarm level (as in smoke detectors) but are a concentration-time function. At lower concentrations (e.g. 100 parts per million) the detector will not sound an alarm for many tens of minutes. At 400 parts per million (PPM), the alarm will sound within a few minutes. This concentration-time function is intended to mimic the uptake of carbon monoxide in the body while also preventing false alarms due to relatively common sources of carbon monoxide such as cigarette smoke. There are four types of sensors available and they vary in cost, accuracy and speed of response; electrochemical, semiconductor, digital and portable. The latter three types include sensor elements that typically last up to 10 years. Preventing CO is the key: DO have your appliances inspected by a registered gas safe engineer.  If you have a working fireplace, ensure the flues and chimneys are properly connected, in good condition and not blocked. DO choose appliances that fumes are vented outside and have then installed as per manufacturers guidelines. DON’T use a gas oven to warm your home, NOT even for a short period. DON’T ignore symptoms, especially if they are being experienced by more than one person. DON’T sleep in any room with an unvented gas heater This is not something to mess with, Carbon monoxide can kill.  Be vigilant and take all possible steps to prevent CO poisoning.