Six people, including an infant, were taken to hospital after a buildup of carbon monoxide was detected in a Calgary apartment building. The Calgary Fire Department responded to the 200 block of 19 Street N.W. around 5:50 p.m. on Tuesday, after a carbon monoxide (CO) alarm was activated. Firefighters investigated and detected carbon monoxide levels as high as 100 parts per million in the building. Approximately 60 people were evacuated from the building. Five people were transported to hospital for assessment and an infant was taken to the children’s hospital by their parents. “The alarm was initially raised by a tenant whose carbon monoxide alarm activated inside her unit. She immediately called 911, which was absolutely the right thing to do. Working CO alarms provide early warning of this invisible, odourless and dangerous gas, and can be lifesaving,” the Calgary Fire Department said in a news release. Upon further investigation, it was determined an earlier cleaning of the parkade combined with an inadequately functioning ventilation system caused the carbon monoxide to build up. Residents were allowed to return to their units after the building was ventilated and inspected. Fire crews cleared the scene around 8:30 p.m. The fire department notes that using gas-powered equipment, such as pressure washers, heaters or generators, in an enclosed or poorly ventilated space is “extremely dangerous.” “These devices can quickly produce lethal concentrations of carbon monoxide, even if operated for a short period. Carbon monoxide is colourless, odourless and tasteless, making it undetectable without a properly functioning CO alarm,” the release reads. Exposure to CO can produce symptoms such as headaches, nausea, dizziness, confusion, fatigue and loss of consciousness.