Of the two security screeners at Vancouver International Airport facing drug trafficking charges, one has a prior conviction – raising serious questions about how he was able to keep his job.

Screeners Gurvinder Singh Pahl and Ajitpal Singh Judge are among three men allegedly involved in a plot to smuggle more than 14 kilograms of the drug ecstasy through YVR earlier this month.

CTV News has learned that 24-year-old Pahl, a Richmond, B.C. resident, was on probation for credit card fraud at the time. Despite his conviction, he was not fired.

Liberal Senator Colin Kenny says the incident highlights a clear gap in the system that must be closed. He says security screeners are only subjected to criminal record checks every five years.

"An awful lot can happen in a five-year period, and someone who has a clean record this year might not have one two years from now," Kenny said.

He also believes similar smuggling attempts fly under the radar on a weekly, if not daily basis in Canada.

"This is definitely the tip of the iceberg," he said.

The International Association of Machinists and Aerospace Workers, which represents screeners at YVR, says the charges are disappointing. They come as the union is working to rally public opposition to Canadian Air Transport Security Authority (CATSA) decision to lay off screeners across Canada.

"There are 800 employees out here. I hope two don't taint the reputation of the other 798," said union representative Ronald Fontaine.

Pahl and Judge are due to appear in court next month. Aerogaurd, the company contracted by CATSA to head security at YVR, is not discussing their case.

With a report from CTV British Columbia's Lisa Rossington