A North Bay family is sharing their story of how a carbon monoxide alarm saved their lives last weekend.

Jessie Embrack and her family went to bed in the evening of Saturday, Feb. 29 without knowing that a silent killer was lurking inside their home. At 2:00 a.m. Sunday morning, Jessie woke up to a sound. Still drowsy, she followed the noise which was now accompanied by a faint voice.

She thought that the kids left a video game on in the basement as she tried to find the source of the sound.

As she approached the furnace room, the message became clear.

"We're very fortunate. It saved our lives absolutely," said Jessie at her house. "We knew the levels were high but we didn’t know the numbers it was on."

The carbon monoxide alarm was alerting her and her family of the deadly gas. Without hesitation, Jessie woke her 10-year-old son Cash, 11-year-old daughter Jaidyn and her husband Jamal, telling them to put on their coats. They quickly left the home with their dog Marley.

Once on scene, fire crews used detectors and found that carbon monoxide levels were high than 170 parts per million and climbing.

"It was very scary. Very scary. My grandparents when I was younger had a scare and that was always going through my head and also I had to get these guys awake. They're the closest things to me," said Jessie.

As CO levels increase and remain above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea. At levels above 150 to 200 ppm, disorientation, unconsciousness and death are possible.

It was determined there was a cracked heat exchanger within the furnace; a problem that only a technician can detect.

When you breathe it in, carbon monoxide prevents your blood cells from carrying enough oxygen. High levels of carbon monoxide can kill quickly, but even low levels can have long-lasting effects. At low concentrations, the symptoms of carbon monoxide poisoning resemble the flu: including headaches, nausea, and fatigue.

The North Bay Fire Department is reminding everyone to make sure their CO alarms are working, as it is the law to have them installed.

"If you have any type of fuel burning appliance or an attached garage, you need a working carbon monoxide alarm, but in the winter, check your vents and make sure your vents aren't blocked," said Fire Chief Jason Whiteley.

Luckily, the Embracks had four alarms working inside their home. They are hoping to spread awareness on how important it is to have functioning alarms.

"Make sure that you have them, don’t take advantage of the fact that maybe somebody got you one and you never used it, actually install them," said Jessie.

The fire department is also reminding people to replace carbon monoxide alarms every five to seven years whether they are hardwired or battery operated and replace batteries annually.