10/15/2014 11:44 EDT | Updated 12/15/2014 05:59 EST

Vancouver overdoses caused by fentanyl, not heroin

Vancouver police say what they at first feared was a bad batch of heroin turns out to be fentanyl which is many times more potent than either morphine or heroin.

Police first issued a warning over the long weekend following more than 30 overdoses including one death.

Now Const. Brian Montague says lab results just back from Health Canada show the substance causing the overdoses is fentanyl, a painkiller 100times more potent than morphine which has been responsible for many overdose deaths over the last several years.

Police have provided photos of the drug packaging being used on the street, but warn that the drug, which is known to be potentially lethal as a street drug, can show up in a variety of ways and in different packages.

They're recommending drug users not consume alone and where possible, use the supervised injection site Insite, which is staffed by medical personnel who can intervene in the event of a drug overdose.