Vancouver Coastal Health announced Tuesday that 31 people overdosed during the previous two days at Insite, the city's safe-injection site.
Samples of the drugs responsible for the overdoses were sent to Health Canada and police say they tested positive for fentanyl.
Police are asking drug user to be extremely cautious and not consume drugs alone.
They say drug users should use Insite, which is staffed by medical personnel who can help in the event of an overdose.
Insite is the city's first legal safe injection site and has been credited by Vancouver's chief medical health officer Dr. Patricia Daly with saving lives and reducing the risk of infection from disease like HIV and hepatitis C.
Vancouver police released these photos of fentanyl, which was first suspected to be heroin, and its packaging that are linked to overdoses.
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