How safe are our airports and can we trust the integrity of our national security institutions?

These, and many questions are being raised after a stunning report out of Quebec found that a handful of employees at Montreal’s Trudeau International Airport were ISIS supporters.

The report highlighted four individuals who were flagged as radicals and eventually stripped of their airport security clearance. One reportedly had extensive knowledge and documentation of homemade explosives and assault weapons.

Another openly supported the Muslim Brotherhood and Islamic State on social media.

Prior to the investigation, carried out by the French-language news agency TVA, these individuals had access to strategic locations, including airport runways and aircrafts.

Following the investigation, these radicals were stripped of their security clearance and moved to different positions in the airport. Two still work there.

They were not arrested or deported. They weren’t even fired from their airport jobs.

Instead, they were moved to less strategically damaging positions.

Apparently, you can be a terrorist-sympathizer in Canada — you can support our enemies who wage war against us — and it won’t necessarily get you fired.

Former police officer and Vancouver-based security expert Leo Knight is ringing the alarm bell. He says similar situations can be found in airports and other ports of entry across Canada.

He calls it a “fundamental flaw in our national security system”.

When individuals apply for security clearance through a federal agency, the government relies on a local background check from the RCMP.

But if a person has spent time outside of Canada, if they come from a failed state or terrorist-producing country, there may be no record of them in Canadian security databases.

“Transport Canada and Global Affairs Canada do not have the capability to conduct thorough background checks in some parts of the world,” said Knight, listing Somalia and Iraq as examples.

Rather than doing an extra thorough background check on those who have spent time in terrorism hotspots, in many instances, the security check skips over those years.

“It’s a gaping hole in our national security,” said Knight. “And it’s one you could drive a truck through, literally, with a bomb inside.”

This report is particularly alarming in the context of recent threats against airlines.

Laptop computers and large electronic devices have been banned on planes traveling from 10 countries in the Mideast and North Africa.

There is reason to believe the threat to Canada runs deeper than just a few rogue airport employees in Montreal.

An access to information request from Rebel Media to Transport Canada, found the number of national security clearances revoked and refused has been steadily rising.

In 2010, there were 31 cases where an individual was refused clearance, and 11 where previously-awarded security clearances were revoked.

By 2015, those figures had jumped to 110 refusals and 42 revocations.

This suggests the report out of Montreal’s Trudeau International Airport may not be an isolated problem. It may be more far-reaching and potentially coordinated.

Our enemies are working to infiltrate our institutions in order to do harm against innocent civilians. We need to take this threat seriously, and do everything we can to stop them.

Correction: In a recent article, I interviewed Customs and Immigration Union (CIU) President Jean-Pierre Fortin. However, I incorrectly identified him as Pierre St-Jacques, the communications director who coordinated the interview. I apologize for this error.