Multiple carbon monoxide alarms force evacuation of southeast Calgary residential building, northeast Calgary home and school

Calgary fire crews responded to multiple carbon monoxide alarms Thursday across the city.

At 11:30 a.m., fire crews were called to a 48-unit residence at 4975 130 Ave. S.E. by a number of residents whose alarms had gone off.

Crews discovered the CO levels were at 200 parts per million (ppm) in the lobby and as high as 520 ppm in the hallways and common areas of the building.

Crews activated fire alarms and everyone in the building was evacuated to a nearby building. ATCO was called to the scene to investigate. It was discovered that a vent was blocked with leaves and other debris that had iced over, causing the CO buildup.

Once the blockage was removed, the building was reventilated and residents were allowed to re-enter their suites.

Earlier in the day, just after midnight, a northeast Calgary family's carbon dioxide alarm went off, causing them to call 911. The family of four, as well as three pets, evacuated while ATCO staff members investigated. No one was injured and ATCO was able to resolve the problem.

Just before 9 a.m., crews were dispatched to a school on Maryvale Road in the northeast. ATCO staff investigated and the school was evacuated as a precaution. The source of the problem was the boiler, where the CO reading went up to 720 ppm. Investigators determined that the boiler needs repairs, but were able to make the school's air quality safe.

At 10:35 a.m., fire crews responded to a CO alarm at a business in the 4300 block of 54 Avenue S.E. for reports of a CO buildup after an employee at a nearby business reported feeling sick and a gassy smell being present.

Adding to the situation was the fact that a business next door was a welding shop.

The source of the problem was discovered to be a gas stove that didn't have proper venting. CO buildup registered 60 ppm. The business was advised to have venting installed by a certified professional.

Just before 11 a.m., fire crews responded after receiving reports of CO buildup at a residential building on Meredith Road N.E. The source of the buildup was a rooftop HVAC. ATCO staff shut it off and ventilated the building. The HVAC unit was shut off until building management can get it fixed. No one was injured.

Carbon monoxide is a poisonous gas that has no colour, smell or taste. The fire department advises everyone to have working CO alarms in their homes that can advise you if there is carbon monoxide buildup.

The most common source of CO buildup is the furnace, but it can also come from appliances that run on natural gas or propane.

Carbon monoxide poisoning symptoms include flu-like symptoms such as headaches, nausea, dizziness, fatigue, confusion and a loss of consciousness. Other things to watch for are stale or stuffy air, moisture on your windows and walls, soot buildup around appliances and vents or a pilot light that keeps going out.