Calgary police say a new drug 100 times more toxic than fentanyl is likely available on city streets.

Police seized a single sample of W-18 late last year, said Staff Sgt. Jason Walker.

"And I can guarantee you, there's got to be more out there. We just haven't seen it yet."

Fentanyl deaths

The seizure comes as Calgary police struggle to deal with the prevalence of fentanyl, an opioid up to 100 times more powerful than morphine.

According to Alberta Health Services, there were 213 deaths fentanyl related deaths in Alberta in 2015. Seventy-four of those deaths occurred in Calgary between January and September of last year.

To date, there are no known deaths related to W-18, but its presence can be difficult to detect.

"They kind of have to know what they're testing for in order to run the proper tests and have a sample to compare it to," Walker said about toxicology tests.

Organized criminals 'not pharmacologists'

Walker adds that only certain labs are able to test for W-18, and there's a chance the drug is being mixed into illegal doses of fentanyl, either intentionally or otherwise.

"There's no oversight with these illicit drug labs," Walker said.

"These organized criminals that are producing these things.... They're not pharmacologists. These are not industrial standards. They're in someone's basement with a pill press mixing powders."