The RCMP is warning residents around Estevan, Sask., that a drug which can be 100 times more powerful than fentanyl was seized from the area.
Police say they seized a substance back in October 2017 and sent it to Health Canada's drug analysis centre for testing.
Health Canada now confirms that carfentanil was found in the substance.
Police warn the drug is much more powerful than fentanyl and 10,000 times more potent than morphine.
"Exposure to a very small amount of this drug could be fatal through ingestion, inhalation or absorption through the skin," reads an RCMP news release issued Saturday.
Police say the drug may still be circulating through southern parts of the province, and urge people not to consume illicit drugs from "unregulated sources."
"Street drugs are often represented as one thing but can unknowingly contain other substances such as carfentanil," say RCMP.
Police have charged a 52-year-old woman in connection with the drug seizure.