Vanessa Robinson lost her two young boys, Chase and Tyler, to carbon monoxide poisoning on a May night three years ago.

She recalls the boys were unsettled that night and got into bed with her.

Ms Robinson woke later, confused and in excruciating pain.

"I managed to drag myself out of bed, thinking that I had to get ready," she said.

"I attempted to have a shower and I came out and I saw my children and I knew that there was something wrong, so I immediately called my ex-husband to come around and the ambulance."

Ms Robinson initially was a suspect over the deaths but as the days went by, police determined the deaths were accidental, caused by a faulty gas heater that leaked carbon monoxide fumes.

The woman is now raising awareness of the risks of carbon monoxide poisoning.

She started the Chase and Tyler Foundation to help spread her message.

"One of the things that hit me when I was advised about what killed my children ... was that there were so many other vulnerable people throughout Australia that had no idea about our own home appliances that could be deadly," she said.

"So I really wanted to take action. Even in extreme sickness and grief I knew that I had to do something."

Servicing of appliances essential

The Office of the Technical Regulator ensures safety for energy consumers in South Australia.

Trevor Tucker from the Office warned people needed to get their gas heaters serviced every two years to ensure no carbon monoxide was leaking into their houses.

"It's usually the effect of ventilation, lack of ventilation in fact," he said.

"Modern buildings in particular are notorious for cutting down the advantageous ventilation as we call it therefore the gas appliance, no matter what type of appliance it is, doesn't get the air it needs to combust properly and then creates carbon monoxide."

The Office of the Technical Regulator said carbon monoxide poisoning often resulted when gas appliances were being used improperly, such as ovens being used as heaters or outdoor gas heaters being taken indoors.

In the United States, it is estimated there are about 500 accidental carbon monoxide poisonings annually.

In South Australia there were 35 cases in the past year, but the figure includes suicide attempts and people affected by smoke inhalation.

Paddy Phillips of SA Health said the symptoms could easily be mistaken because they were similar to the flu.

"The most common one is a headache, but also nausea, vomiting, drowsiness and ultimately unconsciousness," he warned.

"And early signs in children for example is that they can become grumpy and irritable because they can't tell you about their headache, for example."

Professor Phillips said anyone experiencing such symptoms should switch off the appliance or move further away to see if the symptoms ease.