The blaze started around 8:30 a.m. in a heating exchange unit for a cooling tower on the roof of the 35-story former headquarters of Quaker Oats Co.
``It took about 20 minutes'' to get the fire under control, said Chicago Fire Commissioner James Joyce. ``We did fine once we got water on the building.''
Workers were evacuated by building officials, Joyce said, adding that the fire damage was confined to the roof of the building.
``There's really no damage to the building,'' he said. ``There is a little water on the top floor.''
Traffic was detoured for several blocks around the scene. About 100 fire department personnel responded to the scene, Joyce said, adding that investigators did not immediately know how the fire started.
Kristin Gegner, who works for Mesirow Financial on the building's 13th floor, said workers were evacuated shortly after they first heard fire trucks just before 9 a.m.
``It was completely orderly, and everyone was calm,'' Gegner said.
Several employees were taken to a nearby hotel, Joyce said. He said workers were expected to return to the building later on Friday.
