The fire started just after 3 a.m. and was extinguished around 6:30 a.m. No one was hurt or rescued. The fire was burning inside a commercial building at 1326 South Michigan Avenue, and it may have started in the back where renovations are taking place. There are law offices on the top floor.
Michigan Avenue is shut down from Roosevelt Road to 16th Street, with smoke filling nearby streets.
"The guys are making headway. We kept the fire right to where it's at. That's what we call defensive mode, while we offensively trying to protect as much of the building itself," said Gene Ryan, Chicago Fire Department, during the firefight.
At 3:35 a.m., an second alarm was called on the fire due to winds, Fire Media Affairs Chief Kevin MacGregor said.
The flames were heaviest in the rear of the building and have destroyed most of the roof, according to MacGregor, who said a third alarm was called around 4:40 a.m.
Fire crews had four "master streams" on the flames and there were about 80 firefighters on the scene, MacGregor said.
"There is a considerable amount of fire and we've got numerous lines on the fire from various different angles," MacGregor said.
Heavy winds blowing from the south fanned the fire and officials warned people to stay south of 14th Street on Michigan Avenue, MacGregor said.
Winds averaged about 20 mph during the morning hours in Chicago, according to a spokesman for the National Weather Service.
There are several residential high-rise buildings in the area, however, no evacuations were ordered as of 6 a.m., MacGregor said.
ComEd shut down power to building, MacGregor said. Representatives from People's Gas were also on the scene.
The Sun-Times Media Wire contributed to this report.