MONTREAL -- Three workers have died after an explosion Monday at the Bois Ouvré plant in Beauceville, Quebec provincial police said Wednesday.

The victims are Jean Lachance, a 51-year-old man from Saint-George, Mario Morin, 57, of Beauceville and Martin Roy, 50, of Saint-George.

A total of eight people were injured in the incident, which happened after workers attempted to control a fire that broke out while subcontractors were doing repair work on the roof of the plant, located approximately 88 kilometres south of Quebec City. 

The Sûreté du Québec (SQ) says an investigation is still ongoing to determine the cause of the fire that led to the explosion. 

SQ officers were called at 7:30 a.m. to the blaze on 134th Street. Firefighters and ambulance crews were also dispatched to the scene.

Union representative François Cardinal says the organization plans to help "all those affected by this disaster."

"Our members are all in shock," said Local 9153 President Eric Filion.

An investigation by the Commission des normes, de l'équité, de la santé et de la sécurité du travail (CNESST) is also underway.

-- with files from The Canadian Press.