The Chicago Fire Department was called for a fire Saturday in an industrial building at 2823 W. Fulton Street. A power surge was possibly responsible for a the building filling with smoke. Companies were prevented from entering the area of concern until ComEd crews could cut power to the building.
The Chicago Tribune has a brief article HERE. Tim Olk submitted a few images from the scene.

Firefighters wait outside until ComEd can cut the building's power because of arcing in the electric room. Tim Olk photo

As a precaution, Squad 2A was positioned to go to work if the fire took off. Tim Olk photo

Command Van 2-7-1 was deployed on Fulton Street in Sector 1. Tim Olk photo

Firefighters look on as a ComEd worker cuts power to the building. Tim Olk photo

Fire companies had to wait for ComEd to arrive and cut the building's power before it was safe to enter the electric room. Tim Olk photo

Engine 44 was on a hydrant and hooked into the sprinkler system at the Still & Box. Tim Olk photo