Carbon monoxide is a poisonous gas which cannot be seen, tasted or smelt and is therefore extremely difficult to detect. In the last decade, some 251 people in Ireland have lost their lives to carbon monoxide (CO) poisoning – a 35% higher rate of fatalities than England and Wales, per head of population

Often those suffering the effects of CO poisoning can confuse symptoms with other illnesses and indeed, it can often be misdiagnosed with other ailments including flu, migraine or gastroenteritis.

The National Poisons Information Centre (NPIC) in Beaumont Hospital, Dublin says that just 25 of its approximate 10,000 annual enquiries, or just 0.25%, are related to CO illness.

"Approximately half of these calls are from healthcare professionals seeking advice on how to treat (patients)," a spokeswoman said.

"Other than exposure from house fires, the majority of our calls are related to concerns over faulty appliances.

"High levels of carbon monoxide can kill very quickly. Most of our enquiries concern mild symptoms. People with mild symptoms usually make a full recovery."

The gas causes death by starving the body of oxygen – it binds itself to a protein in the blood cells called haemoglobin, preventing oxygen from travelling between the lungs and tissues in the body.

As a result, seizures, coma, heart attacks and, ultimately, death can occur in those exposed to high levels of the gas.

With household appliances a common source of CO leaks, homeowners are advised to check for staining or discolouration as well as gas fire appliances that burn slowly or display a 'floppy' flame.

Yellow or orange flames in place of the normal blue colour, unusual smells when appliances are turned on and loose or disconnected vent or chimney connections or guards can also be signs for concern.