Two workers at an Alcoa smelter northeast of Quebec City have died.
Surete du Quebec constable Marc Butz says a 30-year-old man was assisting with loading procedures at the firm's Baie Comeau port Saturday morning when a one-tonne weight landed on him.
Almost simutaneously, a 57-year-old man suffered a heart attack.
He was pronounced dead at a regional hospital.
Butz added that another man was slightly injured in the collapse.
Transport Canada and the province's workplace safety commission are joining detectives for the ongoing investigation.