It was the second deadly explosion this year, prompting the British Columbia government to announce all sawmills in the province will now be inspected for safety.
Labour Minister Margaret MacDiarmid said she will "send an order out to all the sawmills in the province asking them, telling them, instructing them to inspect from top to bottom their mills, to make sure all steps are being taken to address current safety policy."
Monday's blast killed shift supervisor Alan Little, 43. The BC Coroner's Service identified him in a news release and extended condolences to his family, while noting the family has asked for privacy.
John Nielson was working at the mill when it exploded and knew Little, but declined further comment.
"How would you feel? You work with a person for 30 years. I'm sorry I just need time for myself."
Workers frantically scrambled to help each other after the explosion, with one saying he used scissors to cut charred clothing off those whose burned skin was dripping.
"It was quite gruesome," said Brian Croy, first vice-president of the United Steelworkers Local 1-424, in an interview from his home.
"When you walk out, there was guys with their skin hanging off their arms and stuff from being burned."
Croy said he was among six people inside the mill's lunchroom talking about training when the explosion happened.
"That thing came up so fast, so quick. I don't know where it came from, but it was almost like a cannon going off. It blew through there. It ended just that quick," he said.
While clutching his coat to his face to block the smoke, he managed to escape through a gap in the collapsed wall. Behind him, smaller explosions went off.
"It's almost like you were coming out of the war zone. Everything was levelled. I met that one fellow. I think his fingers were blown off, and his clothing, a lot of it was gone. It was burned off and his hair."
At the first-aid station, injured workers were sitting on a tarp, holding up their burned arms and hands, he said. Some were moaning but others were in shock and were quiet.
Another worker lay on the tarp naked, without any hair and burned black.
Prince George Fire Chief John Lane said it's workers like Croy who were responsible for ensuring the death toll wasn't any higher. Firefighters simply couldn't get into the building to save anyone, he said.
"This was very hot, very concentrated, a great deal of flammable liquid, quite a quantity of hydraulic oil was burning. We also had the added complication ... of those secondary smaller explosions as the cylinders of pressurized gas would heat and expand and then fail and explode."
He said all the patients came out to rescue authorities, rather than rescuers going in to get them.
"I believe fellow workers carried, dragged, assisted those folks that couldn't move or were less mobile out, so they're the true heroes in this."
"The intensity of that fire, nobody would have survived."
The Northern Health Authority said three patients had been airlifted to Vancouver, a fourth was being treated in Edmonton and six remain in Prince George in serious but stable condition. Thirteen others had been treated and released.
"We're devastated by the news of this incident and our thoughts are with our employees and their families," said Greg Stewart, president of Sinclar Group Forest Products.
In all, the company said 24 people were in the sawmill when the blast occurred, a further 16 were in the planer mill next door and four were working in the yard.
He wouldn't speculate on whether his company will rebuild the mill, but he noted it's been an important part of the community for a long time.
"We've had generations of employees that have worked there. One person I heard speak today suggested you can't really go far in Prince George that doesn't have a connection to Lakeland."
Sinclair acquired the mill in 1973. There was a small fire in an outbuilding last month that was caused by dust on a halogen bulb. It caused $25,000 damage and no one was hurt.
Stewart said there was another fire in 2000, but he didn't know much about that one beyond the fact that no one was hurt.
The explosion shattered a quiet evening for Glen Thielmann, who was reading bedtime stories to his kids when the blast occurred.
"It rocked the house and sucked the window shut."
Shortly afterwards, Thielmann walked down the block to join his neighbours, who were watching the flames in the distance consume the mill.
Thielmann said he lives about two kilometres away from the mill site. He estimated the flames had shot more than 60 metres into the air. Hours later, clouds and steam were still pouring from the mill.
Sirens screamed through the night and the air smelled of wood smoke, he said.
According to the company website, about 170 people work at the facility. The sawmill and planer mill complex includes a hot oil energy system for drying lumber.The website said the mill's primary products are premier-grade, kiln-dried studs. The mill also supplies fibre for two bioenergy systems, including the district energy plant.
In January, an explosion and fire killed two workers at Babine Forest Products in Burns Lake, about 230 kilometres northwest of Prince George.
WorkSafe BC is still investigating the cause, but the mill was flattened and 250 people were thrown out of work.
Prospects of rebuilding the mill seem dim.
The mill's owner, Oregon-based Hampton Affiliates, has said it can't rebuild without a guaranteed timber supply, but there is a shortage of useable timber in the area.