Carbon monoxide is a highly poisonous gas which is released during incomplete combustion of combustibles containing carbon compounds. It is colourless, odourless and non-irritating. Carbon monoxide can make you very ill and is potentially lethal.
CO poisoning has a wide range of symptoms (nausea, vomiting, headache, fainting, etc.). This is why CO poisoning is not immediately recognisable. Always be on your guard when you have an appliance in your room that can spread CO (geyser water heaters, coal, gas and fuel oil heaters, etc.). Only electric heating appliances pose no threat.
A few precautionary measures:
If you witness a possible CO poisoning, act quickly: