Monday’s fire at 53 E. John St. was started by an acetylene cutting torch, according to the Champaign Fire Department.

Champaign Deputy Fire Marshall John Kohler reported that a worker was using the torch to cut a cast iron drain pipe in the building.

“It got hot enough where it caught some of the insulation on fire and that was the initial cause,” Kohler said.

The cost of the fire was also revealed to be $1.2 million, including $1 million in structural damage and $200,000 in lost contents.

The blaze “gutted” the third floor of the building and caused water to rise “literally up to the door knobs” on the first floor. Two firefighters suffered injury while fighting the fire.

The Champaign Fire Department derived some teaching points from the incident, pointing out that “This fire was not reported to authorities for at least 20 minutes,” and that “Fire doubles in size every 60 seconds.”