A family of six have been hospitalised after receiving a near-fatal dose of carbon monoxide.

Emergency services were called to a home in the Sydney suburb of Merrylands on Tuesday after reports one of the family members had fallen ill.

It quickly became apparent to paramedics that the those inside, a family and friends consisting of four adults and two boys, were suffering from carbon monoxide poisoning after they all showed signs of drowsiness and nausea and were rushed to hospital.

The family are believed to have been using a charcoal cooker to help heat their home, and had fallen asleep with it still burning.

“Thankfully one person was aware enough to call Triple-0, preventing a potential tragedy,” NSW Ambulance Inspector Andrew McApline said.

Fire and Rescue NSW later shared a photo of the barbecue used inside the home and urged people not to rely on these appliances as indoor heaters.

“Never bring outdoor heaters or cookers inside and never rely on charcoal beads for heating in confined spaces,” it said.

This comes just weeks after NSW Health issued a warning about the dangers of potential carbon monoxide poisoning during an especially cold winter.

“Burning charcoal, BBQ coal outdoor heaters, and portable backup generators (indoors) are some of the biggest concerns,” Dr Richard Broome, Director of Environmental Health at NSW Health, said.

Victoria’s former Director of Energy Safety, Paul Fearon, branded carbon monoxide the “silent killer” following a spate of poisonings.

Dr Christine Cowie, a Senior Research Fellow at the University of NSW’s Centre for Air Quality and Health Research and Evaluation, told Yahoo News that there is “no advanced warning” for poisonings due to carbon monoxide’s odourless gas.

When the gas does take control of the body, symptoms, such as headaches, tiredness and vomiting, are often confused with the flu, Dr Cowie explained, which can in turn prove fatal if not acted on immediately.

Image credits: Nine News

This article first appeared on OverSixty.