The Ministry of Health has issued an overdose alert for Saskatoon and area after 90 calls for service were received between Friday and Monday.

A release states that these incidents required critical medical intervention including multiple doses of naloxone, CPR, and ventilation. Firefighters observed an escalation in cases and severity of interventions required each day, and the substance in question is unknown.

The Saskatoon Fire Department says it is aware of other local resources responding to an increase in overdoses.

The alert expires on July 28th, unless prolonged.