A chlorine leak caused a HazMat situation that shut down several streets in the Loop and injured six people Friday morning.
A Level 2 HazMat response was called about 10 a.m. at the intersection of Wacker and Clark, according to Fire Media Affairs.
Chicago Fire Department spokesman Larry Merritt said the situation started when chlorine and acid were accidentally mixed on the roof of the building at 77 W. Wacker, causing a chlorine leak.
It was not immediately clear how the leak occurred.
Five people were taken to Northwestern Memorial Hospital and one to Rush Medical Center, all in fair to serious condition with respiratory issues. Merritt said the injuries do not appear to be life-threatening.
Several streets in the area were closed, but Clark and LaSalle were reopened just after 11 a.m. Upper Wacker remains closed between Clark and LaSalle.
77 W. Wacker is a 49-story office building, formerly known as the United Building.