CFD said a truss roof on a building in the 4100-block of North Milwaukee Avenue came down.
No injuries were reported, CFD said.
Tim Levan is marking a miracle. He was inside this husk of a building, what was once Nu-Life body shop, when the roof started to collapse.
"Loud boom like a hurricane. Like a twister coming through," Levan said.
Levan said a customer pulled him from his seat as a cloud of smoke and dust rumbled forth. However, Levan still had the wherewithal to pull two cars out of the shop before the roof caved in.
"All of a sudden I see the heater come down," Levan said. "I wasn't thinking... I seen a cloud of smoke, I was thinking about the cars... take 'em out."
According Chicago's department of buildings, required roof repairs were not made and the building should not have been occupied after a lawsuit was filed for building code violations in 2015.
Chopper 7 was over the damaged building Thursday morning, where most of the roof could be seen obliterated. On the ground, the rest of the shop in shambles shocking those passing by.
"The whole roof came down the beams the roof everything," Jesus Vilella said. "If you look further in there those are beams solid steel. That comes down and hits you, forget it."
Levan is mourning the loss of the building he's worked in for more than three decades.
"Thirty one years. 1993. Now I've got no job," Levan said.
He is alive and counting his blessings Thursday night.
"I'm glad the three of us didn't get hurt," Levan said.
The exact cause of the collapse was not immediately known.