The Gateway Postal Facility, in Mississauga, Ont., is the front line in a growing, and sometimes controversial, fight against fentanyl and other illegal opioids.

Thousands of packages in bland yellow, white and brown roll off of conveyer belts at the sorting station every minute, with more stacked waiting to be delivered.

But it would be a mistake to think that all of them are bills and purchases from Amazon, because street drugs are flowing into Canada by mail, including the powerful and potentially deadly opioid fentanyl.

Packages already being opened

The federal government is set to increase the powers that Canada Border Services Agency has to open mail and snoop inside with Bill C-37.

CBSA officers are already examining packages, alongside Canada Post employees, in a secure underground sorting room inside the Mississauga sorting centre, one of the largest postal facilities in North America.

CBSA officers sift through and analyze the packages, setting aside some to be poked, X-rayed, even opened. By law right now, they can open only packages. Letters that weigh 30 grams or less can't be touched without a court order or permission from the addressee.

Carmen Alexander-Nash is CBSA chief of operations at the Canada Post sorting station in Mississauga, Ont., where officers screen packages for drug shipments. (CBC)

X-ray can show drugs shipments

Because criminals in China are responsible for much of the fentanyl flooding into Canadian streets, country of origin is a red flag. Officers also check against a database of suspicious senders. Then, it goes into the X-Ray machine — similar to one you might see at an airport.

"You will see, often, it's out of place, it's an odd shape," says a veteran CBSA officer who asked to remain anonymous.

X-rays show this package may contain doda or opium. (CBC)

When she sees orange circles on the scanner's screen, she suspects a drugs shipment.

"Like this one, I can definitely tell that it's organic material. By the shape of this, I'm positive of what we are opening up here. Doda, opium. So I definitely want to open that one," she said.

After the package is opened, her suspicion is confirmed and it is set aside for further investigation, or destruction.

If she suspects fentanyl, her work stops immediately.

Fentanyl is a fine powder and can be sent in a standard envelope. (Nanaimo RCMP)

"That will be sent to the lab (in Ottawa), no opening," she says. "Even the smallest granules could kill us."

Because fentanyl is small enough and light enough to fit inside a standard envelope, the size of package that can be opened has become a big issue.

Opium, heroin or meth and marijuana are heavy and take up space, and when criminals mail them, they must use a package.

Why Ottawa wants to change law

But federal law says letters of 30 grams or less can't be opened without a court order, even if a CBSA officer suspects fentanyl is inside.

"It can be a challenge if we identify an importer or exporter and we know there is suspected narcotics inside," says the CBSA's chief of operations at the sorting station, Carmen Alexander-Nash.

There is another way the law allows. "We can write to ask permission."

That's right: CBSA has to send a letter to a suspected drug dealer, asking for permission to open the letter to prove they're a drug dealer.

Ottawa's solution, contained in Bill C-37, now through second reading in the House of Commons, is to allow CBSA officers to open all mail coming from other countries, packages and letters.

Public Safety Minister Ralph Goodale says the danger from fentanyl is too great to leave the law as it is. "A pack of 30 grams is enough fentanyl, for example, to kill 15,000 people."

Bill C-37 also outlaws pill presses, and contains enabling legislation allowing safe injection sites to open.

Public Safety Minister Ralph Goodale says even a trace amount of fentanyl can kill. 'A pack of 30 grams is enough fentanyl, for example, to kill 15,000 people.' (CBC)

Privacy at risk

The Canadian Civil Liberties Association has no quarrel with the parts of the bill covering pill presses or safe injection sites, but draws the line at allowing letters to be opened.

"Right now guards have the right to examine an envelope without opening it," says Sukanya Pillay, executive director of the Canadian Civil Liberties Association.

"If there's reason to suspect that it contains powder or some kind of substance, get a warrant. That's all we're saying, get a warrant. It's simple."

Other privacy experts, like Toronto lawyer Stuart O'Connell, say that expanding what's searchable would probably stand up to a constitutional challenge, so long as CBSA agents refrained from reading the letters inside.

Reading letters would almost certainly trigger a Charter challenge, he said.

The debate on this is expected to go on for months as MPs — and Canadians — decide whether they want to give up more of their privacy for protection against a killer drug.