Test results confirm a substance thrown at a police officer in Sault Ste. Marie, Ont., was fentanyl.
As a result, a man arrested in December is facing further charges.
Police say the incident occurred when they were arresting the man on drug-trafficking charges.
They say he broke open a bag of fentanyl and spread the potentially lethal drug on the officer's police vest.
A search of his vehicle turned up fentanyl, a shotgun and pepper spray.
In addition to other charges, he now faces two counts of mischief endangering life.