THE Chief Medical Officer has issued a warning about the dangers of carbon monoxide.
Dr Michael McBride issued the reminder as people are making greater use of their heating.
The message comes after a year which has seen a number of tragedies because of the deadly gas.
Newtownabbey teenagers, Aaron Davidson and Neil McFerran died at a holiday home in Castlerock in August from carbon monoxide poisoning.
Dr McBride said: "You should make sure that your heating systems are properly maintained and serviced, especially in the current cold spell, and ensure that they are used in properly ventilated spaces.
"Carbon monoxide poisoning causes a number of deaths and hospital admissions each year in Northern Ireland. The recent tragedies are a stark reminder that carbon monoxide can be lethal."
He added: "It's vital that we are all vigilant to ensure that we are protected from the dangers of carbon monoxide poisoning.
"That is why the Department of Health has produced a new guide - Carbon Monoxide: are you at risk? - which is available to download from http://www.nidirect.gov.uk
"Of course prevention is always better than cure, and the guide contains important information about measures that can be taken to prevent carbon monoxide poisoning from occurring."
The Chief Medical Officer concluded: "Everyone needs to be aware of the symptoms, because it can easily be confused with other common conditions. The guide provides clear, simple information on how to spot the warning signs."