It took a crew of 35 firefighters about five hours to extinguish a large fire that broke out early Wednesday morning at a bus depot in Oshawa.

Fire Chief Stephen Barkwell told reporters at the scene that a call came in at about 2:20 a.m. from a worker at Durham Region Transit’s Raleigh Depot who reported seeing “heavy smoke and flame.”

Barkwell said shortly after arriving at the scene at 710 Raleigh Ave., which is south of Highway 401 and east of Farewell Street, the incident commander upgraded the industrial fire to two alarms resulting in their “complement (being increased) by two more firefighting apparatus.”

Not long after that, the fire was upgraded for a second time to three alarms and two more apparatuses were brought in, he said.

The fire destroyed a three-bay section of the structure and caused the roof deck of that building to collapse.

An unknown number of buses were also damaged by the fire and as a result several routes have been impacted. A full list of changes can be found online.

“The crews did an amazing job this morning. … They did a fantastic job,” Barkwell said, adding their efforts helped stop the fire from spreading to other sections of the building.

Firefighters remain on scene at this time to monitor for any hot spots. Heavy machinery is also being brought in to pull apart the building as part of that effort, he said.

It is not yet known exactly where the fire originated and there is also no estimate available for the cost of the damages it caused.

The Ontario Fire Marshall has been notified.

Farewell Street remains closed south of Bloor Street to Wentworth Street and people are being asked to avoid the area.