The Calgary Fire Department said high levels of carbon monoxide were detected at a mechanical shop, from which three people were taken to hospital late Tuesday afternoon.
A spokesperson for CFD said firefighters were called to the shop at 940 48 Avenue S.E. at 5:45 p.m. by someone who said workers inside were not feeling well.
“On arrival, firefighters were met by a worker complaining of illness and explaining that co-workers were losing consciousness inside the commercial shop,” CFD said in a news release issued Tuesday night. “Firefighters entered the building utilizing self-contained breathing apparatus and found two more workers exhibiting low levels of consciousness and feeling ill.
“Fire crews removed the injured workers.”
The fire department later confirmed the three people taken to hospital were workers. Their condition was not disclosed.
“We were very fortunate that one of the employees off-site received some information from the people here that they weren’t feeling well and they quickly called 911,” Keith Stahl, a battalion chief with the CFD, told Global News at the scene.
Inside the shop, the CFD recorded carbon monoxide levels of about 600 parts per million as well as “other dangerous gases.”
READ MORE: What you need to know about carbon monoxide poisoning
According to the CFD, the Hazardous Materials Response Team was called in to ensure the facility was safely evacuated.
“As a precaution, fire crews evacuated adjacent business(es) and set up a secure perimeter,” the CFD said, noting that police and Alberta Health Services assisted.
“Later investigation determined that a heater burning a recycled alternate fuel had malfunctioned leading to the release of high levels of carbon monoxide, decreased oxygen, sulfur dioxide and other exotic gases. Crews were able to vent the structure and ensure a safe environment for investigators.”
The CFD said it is still investigating.
Carbon monoxide is an odourless, colourless gas. The Health Canada website says being exposed to high levels of carbon monoxide can lead to convulsions and possible put someone in a coma or even kill them.
Watch below: Some Global News videos about carbon monoxide.