A worker is dead after a late-afternoon explosion at the Terrace Bay Pulp mill on Monday.
Ontario Provincial Police have not released the employee's identity.
Two other people were taken to hospital for non-life threatening injuries.
Ontario Ministry of Labour spokesperson Greg Dennis said details are preliminary until investigators can confirm what happened.
Dennis said it appears the explosion was in a blow tank, a large cylindrical container in which cooked wood chips are blown after coming out of a digester during the pulp process. Residents reported hearing a loud explosion and seeing black smoke.
"This is a terrible thing and our sympathies go out to the family of this ... young worker," Dennis said.
The Ministry of Labour, Ontario Fire Marshall's Office, Coroner's Office and the OPP are all investigating.