Concerns over the powerful opioid fentanyl have left some customs agents too afraid to screen certain packages.

CBSA officers are responsible for screening suspicious packages at all entry points into the country, from border crossing and airports to mail sorting facilities.

With law enforcement officials believing fentanyl is produced at labs abroad, the concern is screening officers could come into contact with a more concentrated form of the drug as it enters Canada.

"What we're telling our officers at this time, from a health and safety point of view, is that if there's a package and they think there could fentanyl, they shouldn't touch it. They shouldn't approach it," said Jean-Pierre Fortin, president of the Customs and Immigration Union.

Even small quantities of fentanyl can be extremely dangerous. Last month, the Vancouver Police Department announced it would be training and equipping its officers with Narcan, a powerful opiate antidote. At that press conference Acting Sergeant Brian Montague revealed three VPD officers have been hospitalized for fentanyl exposure while responding to overdoses, two of them overdosing.

When customs agents are concerned a package might contain fentanyl, they leave it for supervisors to deal with at Canada Post’s international mail sorting facility at Vancouver International Airport.

Canada Post did not respond to questions from CTV News about how many packages are affected.

While there is currently a policy in place for how customs agents should deal with the fentanyl, Fortin said there's still a lack of tools or training available.

"The border is actually the first line of defence of this country, so obviously we need to be trained like the firefighters, like the police," he said. "We need to approach this so our officers have the right tools, right training and the right equipment."

Fentanyl has been blamed for roughly 60 per cent of the deadly overdoses recorded in B.C. so far this year, and is considered much more dangerous than heroin. From January to July alone, the BC Coroners Service says 433 people died from overdoses. BC’s chief provincial health officer declared a public health emergency in April due to the volume of fentanyl deaths.

CTV News asked the CBSA for an interview on workers' safety concerns, but the agency refused and said it would email a written response at a later date.

With a report from CTV Vancouver's Penny Daflos