An early-morning fire at a City of Toronto building in Scarborough Tuesday has caused an estimated $5-million to $10-million worth of damage.

Toronto Fire crews were called to Ellesmere Yard, a multi-building complex at Midland Ave. and Ellesmere Rd., at 1.54 a.m. Tuesday. The call was made after an employee filling a fuel tank heard popping sounds coming from inside the building at 1050 Ellesmere Rd., and saw flames.

The call to was quickly upgraded to a two-alarm, with 12 fire trucks and 45 firefighters bringing the blaze under control by 3:15 a.m. Crews remained at the scene well into the morning rush hour, putting out hot spots on the tar roof.

The affected building, which is near a refueling station used by City of Toronto vehicles as well as Toronto Fire, houses eight large hangars used to store city vehicles including garbage and dump trucks, a Toronto Fire spokesperson said.

The fire appears to have started in one of the vehicles and then spread, although the cause of the fire hasn’t been determined yet.

There is heavy damage to the roof of the building, parts of which have caved in. Toronto Fire also said that at least one city pickup truck and one dump truck are “write-offs,” and that several other vehicles have been partially damaged by smoke or flames.

There were no reports of serious injuries. One firefighter suffered a minor back strain but continued working.