BEAUCEVILLE, Que. - CBC Canada has reported that six people were killed as a result of Monday's wood processing plant explosion.

Three of the victims were employees, who were killed in the explosion or very soon after. Three others - still unconfirmed on whether or not they were employees - died the following day after being taken to a nearby hospital. Three more remain in critical condition.

The explosion took place at Séchoirs de Beauce, a wood manufacturing plant operated by the Matra Group. The plant specializes in transforming finger-jointed wood into door and window components. 

An investigation looking into the cause of the explosion is underway. Investigators do know that several workers were trying to extinguish a fire that broke out in one of the plant's buildings when the explosion occurred.

The Matra Group manufactures doors and windows components as well as primed siding and trims from Eastern White Pine lumber. With two plants and over 170,000 sq. ft. of production space, the company processes more than 30 million board feet of conifer each year.