Furnace to blame for high CO levels that forced evacuation of Calgary home

The First Alert Onelink Wi-Fi Smoke + Carbon Monoxide Alarm is displayed at CES Unveiled on Monday, Jan. 4, 2016, in Las Vegas. (AP Photo/John Locher)

The Calgary Fire Department is warning of the dangers of carbon monoxide after a close call in the community of Marlborough on Wednesday.

Emergency crews were called to a small bungalow on Marcombe Drive N.E. at around 8 a.m. after the residents noticed their combination alarm, which detects smoke and carbon monoxide, was going off.

Though none of them could smell smoke or see any fires, they called 911 and left the home.

According to the fire department, initial CO levels inside the home were 130 parts per million (ppm), and later climbed to 160 ppm.

Firefighters determined the CO was coming from the furnace, which they shut down.

Fire crews ventilated the house and waited for ATCO to arrive.

EMS assessed the 12 residents from the home (four adults and eight children, including an infant) but none of them required transportation to the hospital.

"Had the homeowner/landlord in this incident not ensured that there were working smoke/carbon monoxide alarms in this home, the outcome of this emergency incident could have been very different with a potentially tragic outcome," said the fire department in a news release.