A Winnipeg firefighter was treated in hospital after being exposed to a substance believed to be fentanyl earlier this week and is still off the job.

On Wednesday evening, firefighters responded to a report of an unconscious driver in a vehicle on Arlington Street, United Fire Fighters of Winnipeg president Alex Forrest said.

One firefighter who came into contact with the patient immediately started displaying symptoms of opioid poisoning, Forrest said. The firefighter was taken to hospital, treated and released.

"He's still suffering from the effects today and he'll be off for at least one more day," Forrest said Thursday.

Winnipeggers ought to be aware emergency workers respond to suspected fentanyl calls "every single day" and the epidemic should not be considered normal, he said.

It's not the first such case in Winnipeg.

In November of last year, a Winnipeg firefighter-paramedic had to receive emergency treatment after he was exposed to what might have been fentanyl on the job.