Both workers trapped in a silo under collapsed scaffolding at the Domtar factory in Windsor, Que., about 120 kilometres east of Montreal, have been found dead, according to provincial police and the company.
Rescue teams first recovered Yan Baillargeon on Wednesday. The body of the second victim, Hugo Paré, was recovered overnight.
"This tragedy affects us all. This is a day of mourning," Domtar's general manager Sylvain Bricault said at a news conference on Thursday.
"Our thoughts and sympathies go out to the families of Mr. Paré and Mr. Baillargeon and to all colleagues affected by this tragic accident."
Baillargeon, 39, lived in Quebec City, but was originally from Saint-Anselme, a little under 30 kilometres southeast of the province's capital.
In a Facebook post, his sister, Kim Baillargeon, thanked people for their support, saying her brother "left for a better world, in heaven with our father. See you on the other side big brother. I love you infinitely."
Paré, 22, came from Sainte-Catherine-de-la-Jacques-Cartier near Quebec City.
The workers had been buried under the debris of a 20-storey scaffold structure that collapsed at around 1:35 a.m. ET Tuesday at the plant.
Carefully searching the debris
The fear that more equipment could collapse was slowing rescue efforts, authorities said Wednesday.
The rescue mission was complicated by crews' need to secure parts of the scaffold that were still standing before they could continue their search inside the 60-metre-high silo, said Stéphane Simoneau, the director of Sherbrooke's fire protection department.
His department had been assisting with rescue efforts, along with the Windsor firefighting service and the plant's specialized rescue brigade.
Simoneau compared the situation to dealing with a house of cards. He said reaching the area and removing the debris was hard, because there are only three small entry points to the silo.
Rescuers did not want to cause another collapse, he said.
"We have to be careful, you understand, for the rubble, as we take out one piece at a time," he said.
And before they could even start the search, responders had to control the level of oxygen and the temperature inside the silo to make sure the workers and the rescuers would stay safe, he said.
The two victims are part of a contractor's crew hired by Domtar to do major maintenance work on the plant.
The plant's general manager, Sylvain Bricault, would not reveal what company they were associated with during a news conference on Wednesday, saying the accident was still under investigation.
Quebec provincial police and the province's workplace safety board (CNESST) are trying to determine what caused the collapse.
The coroner's office will also be investigating the deaths, as they were deemed accidental.
In a statement, Domtar says it is fully co-operating with authorities and participating in the ongoing investigation to determine the cause of the accident.
A spokesperson for the workplace safety board, Dany Grondin, said it could take up to six months before a report with more details on what happened is released.
About 10 more people were hurt in the accident, including three who were taken to hospital, according to paramedic Alexandre Allard, who works for Dessercom, the ambulance service that responded to the scene. He said they were expected to recover.
Bricault said psychological support services were offered to the workers and the families of the victims.
The plant employs about 900 people in the region and is one of Canada's largest pulp and paper plants.