Winnipeg police are warning the public that a drug sometimes called “drop dead” and another drug known as “grey death” can be as deadly as their names suggest.

Grey death is a combination of drugs like fentanyl and cocaine with the synthetic opioid U-47700. It sometimes resembles chunky concrete.

Grey death hasn’t yet been seized by police in Winnipeg, but Insp. Max Waddell said he has no doubt it has arrived in the city.

There was one known death from U-47700 in Manitoba in 2016, according to the office of the Chief Medical Examiner of Manitoba.

Police across Canada made 254 seizures of U-47700 in 2016, according to Health Canada. The government has proposed adding it to the list of illegal drugs under the Controlled Drugs and Substances Act, which would make possession illegal.

Drop dead, meanwhile, is the local nickname for carfentanil, according to Winnipeg Police Chief Danny Smyth. It was the primary cause of nine deaths in Manitoba in 2016, the Chief Medical Examiner of Manitoba said.

Carfentanil is about 100 times more powerful than fentanyl, which can also be deadly. It is typically used to treat large animals like elephants.

Winnipeg resident Lee Sammons says he hasn’t heard of grey death, but used drop dead last year and ended up suffering a stroke.

“I just wanted to see what all the hype is about,” he said. “Just a pinhead size amount I smoked and I almost died from it.”

Sheri Fandrey, from the Addictions Foundation of Manitoba, says grey death is “significantly stronger than heroin.”

Even if it is made illegal, she said she expects more synthetic opioids to hit the streets.

“There are hundreds, if not thousands, of other potential opioid products that could emerge in our landscape in the near future,” according to Fandrey.

Grey death has killed dozens of people in the U.S, mostly in New York and North Carolina.

There were 2,458 opioid-related deaths in Canada in 2016, according to Health Canada.

With a report from CTV Winnipeg’s Sarah Plowman