Fire crews were still on-scene at the St. James Industrial Park Tuesday morning, 24 hours after a fiberglass manufacturing plant caught fire.

Crews were first called to the industrial building on Sherwin Road early Monday. The area around Omniglass was closed off around 4 a.m, it reopened around 10 a.m..

When firefighters got to the scene, the building exploded. A number of firefighters were blown from the building, injuring three. One of the injured firefighters was taken to hospital for treatment and was later released.

Omniglass makes and distributes fiberglass. The building is full of explosive materials. "The whole building is structurally damaged, walls were blown out," said the platoon chief, Brian Somers.

Omniglass's president, Laurie Davies said the company manufactures 24 hours a day but because Monday was a holiday, there was nobody in the building at the time of the fire.

"I could tell something serious was going on," said Davies. "The fire trucks and the streets were cordoned off."

When he pulled up to his building he said there was a lot of smoke and flames up to 20 feet high.

He founded his company in 1983 and said nothing serious has ever happened. Now he's looking at what can be salvaged.

"There's a newer part in the back and it doesn't seem to be damaged," said Davies. "We have equipment back there so we may, hopefully, be able to maintain some production."

Davies estimates the fire could potentially have cause upwards of $5 million damage. "I just want to get things running as soon as we can and people back to work and back to normal," he said.

The cause of the fire is under investigation.

-With a report from CTV's Jillian Taylor