BARRIE, ONT. -- Officials with Grey Bruce Public Health have issued an alert after a spike in opioid overdoses in Owen Sound.

Preliminary data shows seven people overdosed in the span of five days, a figure the local manager of harm reduction says is higher than usual.

None of the overdoses have been fatal. But Ian Reich is concerned by how long the effects of the overdoses have lasted.

Reich suggests some local drug supply may be contaminated with benzodiazepine, a Naloxone-resistant sedative.

"Naloxone is great to reverse the opioid overdose, but not the benzo one," Reich writes. "Only time and medical intervention can help with that."