LONDON, ONT. -- The Grey Bruce Health Unit is warning residents about two fatal opioid overdoses, pending coroner confirmation, within the past 48 hours in Owen Sound.

Officials say there may have been up to seven fatalities connected to fentanyl or carfentanil this year alone.

In one overdose, a yellow chalk-like substance is suspected to be the cause. Purple, green, and pink variants of the drug have also surfaced.

Drug users are warned to always avoid using alone, never mix drugs and use smaller amounts.