Winnipeg's airport was evacuated just after 4:30 p.m., but officials say it was just a precaution.
An announcement told passengers at the Richardson International Airport to evacuate the building just after 4:30 Saturday afternoon.
"An air conditioning unit failed which created some smoke — as a result out of an overabundance of caution we evacuated just so we could assess it," said Winnipeg Airports Authority spokesperson Tyler MacAfee.
CBC reporter Jaimie Kehler said the period of time from when the evacuation order was issued to when word came that it was OK to return inside was "fairly chaotic," with people dispatched to the sidewalks with their luggage.
There was little information available during this time.
The evacuation triggered long lines at security as passengers who had already checked through had to repeat the process.
It was unclear if any flights were cancelled or delayed significantly.
The failed air conditioning unit was not located in a public area, MacAfee said, but when smoke is spotted in the facility protocol is to begin an evacuation.
"The biggest thing is if there is any kind of issue we want to get everyone out of the building and make sure people are safe," he said.
Please see this update on today's occurence. Thank you for your patience as we return to normal operations. pic.twitter.com/z2DRQGkliA— @YWGairport
Just after 4:50 p.m. people were allowed back inside. MacAfee said there would be short-term delays for passengers who would have to go back through screening before catching their flights.
He said there will be full assessment and investigation of the air conditioning unit.