The first evacuation of its kind at the Winnipeg airport Saturday underscores the urgency in which striking workers are needed back on the job to ensure passenger safety, a union spokesperson says.

"I think the evacuation was actually the first sign to the public that everything is not business as usual behind the scenes, despite what the airport is telling passengers and the travelling public," said Marianne Hladun, regional executive vice-president for the Prairies with the Public Service Alliance of Canada.

Hundreds of passengers were forced outside of the Winnipeg James Armstrong Richardson International Airport Saturday, about four weeks after 150 airport employees went on strike.

Winnipeg Airports Authority spokesperson Tyler MacAfee said Sunday that the source of the smoke was from a malfunctioning piece of equipment called a harmonic filter. He previously said the cause of the evacuation was related to an air conditioning malfunction.

Huddled masses of passengers were eventually allowed back in to board flights, but Hladun said at least 17 planes were delayed before that happened. 

Flights delayed

A number of flights were delayed as a result of the evacuation, MacAfee says, including one that was delayed an hour and another that was delayed two hours. The rest were only delayed by about 20 minutes, he added.

Bruce Bell

Bruce Bell is an electrician at the airport and one of about 150 employees who have been on strike since July 24. (Julianne Runne/CBC)

"We apologize to the passengers that were inconvenienced," MacAfee said. "It's a difficult situation. We don't want to see anyone have a delay like that leaving from the airport, but the biggest thing to us was to make sure that everyone was safe, and that we got everybody back through as quickly as we could."

Hladun said workers who routinely monitor temperature and ventilation systems would've likely been alerted to the issue through a system of alarms before an evacuation was necessary.

"It should never have gotten to a point of evacuation," she said. "This was the first evacuation since this new terminal opened and so that tells me that there was absolute concerns. Either someone didn't know how to respond to the alarms, or they didn't do it properly."

'They're struggling'

Bruce Bell, an electrician who works at the terminal, echoed Hladun's concerns, saying it's "quite likely" that the issue would've been caught by the usual workers had they not been on strike.

"It is kind of showing how our management is very much having difficulty trying to do our job without it," he said, adding he wants management with the airport to come back to the table and negotiate a "fair contract for all."

Tyler MacAfee

Tyler MacAfee is a spokesperson with the Winnipeg Airport Authority. (Julianne Runne/CBC)

"They're struggling and they don't have the expertise that they should have there. It's a little scary for everybody."‚Äč

Hladun also alleged evacuation procedures weren't followed strictly and that some passengers bound for the U.S. were not forced to go through another round of security check as domestic passengers were upon re-entry into the airport.

"They were put on to the tarmac, having access to potential security risks, and then they were put on a plane and sent to the U.S. That's a significant security breach, and I really hope that Transport Canada and the Minister of Transport take this seriously and ask this airport why they didn't follow appropriate evacuation," Hladun said.

But MacAfee said that isn't the case and that the airport authority followed evacuation procedures.

"The accurate information is it depends if the passenger had to go out of the hold room and then go back in, so my understanding is the U.S.-bound passengers never had to leave the screened area, and so they didn't have to go through the screening process again," he said.

"For the union to be commenting on this, they weren't at the event, they don't have the situational awareness, they haven't been briefed on exactly what happened, so for them to have a comment on the procedure, of the process of this, I don't think is accurate."

'Deep dive' review forthcoming

Hladun said she wants passengers travelling through the airport to remember that striking workers are valuable assets to the airport and should be regarded as such.

"The work that our members do is what keep this airport safe and what them being on strike," she said. "They're the ones that have spent decades working here and they know the airport inside and out, and a contractor coming in on a one-time basis cannot ensure their safety the way our members can."

MacAfee said the airport authority will be reviewing the issue this week.

"It's something we're going to be reviewing and we'll be going through this week, taking a deep dive into the process, all the things that happened, to make sure we refine our process going forward."

With files from Kelly Malone