Officials in Alberta are warning the public about the emergence of a deadly new drug called W-18.

Health experts say the substance is about 100 times stronger than fentanyl -- another synthetic opioid that has been linked to hundreds of deaths in Canada over the past year. W-18 is also considered 10,000 times more powerful than morphine.

Even a small amount could be deadly, experts say.

Staff Sgt. Dave Knibbs said the RCMP seized about four kilograms of W-18 powder during a fentanyl investigation in December. That’s enough to make “hundreds of millions” of pills that could have been sold on the streets, Knibbs told reports on Wednesday.

Pills containing the opioid were also found in Calgary earlier this year.

Now, health experts are urging the public to be careful with all street drugs as they could contain W-18.

“Our message to the public is this: no matter what drug you use, fentanyl or W-18 may be hiding in it and they may kill you,” said Dr. Laura Calhoun of Alberta Health Services.

Calhoun added that experts are rushing to find a way to test if W-18 has been ingested.

“W-18 is not part of routine drug testing and cannot be detected urine drug tests,” she said.

Doctors preparing for more overdoses

Emergency room doctors across the province are preparing for a potential rise in overdose cases resulting from the drug.

AHS has also sent a memo to its front-line staff explaining how naloxone, an opioid antidote, could be used to help those who have overdosed on W-18.

In 2015, 272 Albertans died as a result of fentanyl use. And health experts in the province are warning that the effects of W-18 could be even worse.

“It’s scary. I don’t know how else to put it,” said Brent Lloyd, clinical manager at Calgary’s Edgewood Health Network. “Fentanyl has already taken enough lives.”

The fact that W-18 is not yet a controlled substance is also adding to the worries. That means the drug is technically still legal to possess and sell in Canada.

Alberta’s health and justice ministers say they’re working closely with the federal government to “expedite” the process of making the substance illegal.

Lloyd said the decreasing availability of less potent opioids is partly to blame for the rise of drugs as toxic as fentanyl and W-18.

As powerful painkillers such as OxyContin and Percocet become more difficult to get prescriptions for, those addicted to these kinds of drugs are taking risks with more toxic street drugs such as fentanyl and W-18, he said.

But Lloyd and other health experts are urging the public to avoid these substances and seek help if necessary.

“You are putting your life at risk if you think that you’re even just experimenting with a drug like this,” he said.

With files from the Canadian Press and CTV Edmonton