The Ontario Fire Marshal has been called in to help investigate a fire in Stratford that destroyed a building early Monday morning.

Four firetrucks and 25 firefighters were called to the Monteith Avenue scene around 2:40 a.m. Monday.

Crews eventually had to use an excavator to tear apart the building to get at hot spots.

Officials say no one was injured and a damage estimate is unknown.

The building was being used by an asphalt resealing company and fire fighters say there was a lot of combustible material on site, making the fire difficult to control.

“Some miscellaneous containers started to explode inside the fire, so we backed out for safety reasons and went completely defensive from that point forward, protecting the other structures around that business,” Stratford Fire Chief John Paradis said. “[It] got to the point where we’ve had to call in an excavator to try and break up the material left in the building so we can fully extinguish the fire.”

Images from early Monday morning show massive flames pouring out of the building.

Officials say along with the combustible material inside, there was also a lot of wood being stored on site. The cause of the fire is still being investigated.

“Typically of any industrial or commercial businesses like this, it could be something as simple as a Lysol can, to including – even propane tanks. The explosions weren't that big so we are ruling out propane tanks. But it could be very simple material to material that we wouldn't want to be too close to. So that will be found out during the investigation,” said Paradis.

At 4:20 p.m., Paradis said public works crews were sweeping up any debris remaining on the roadway and reopening streets in the area.

The Ontario Fire Marshal's office is assisting the Stratford Fire Department with the investigation.