No one was injured when a window shattered on the 53rd floor of an office tower in the Loop Thursday morning, officials said.
Firefighters were called to the Three First National Plaza at 70 West Madison around 11:10 a.m., according to Fire Department spokesman Larry Langford. The building is 57 stories high.
He said the window shattered but fire officials aren't sure of the cause. "I have absolutely no idea what shattered a window way up there," Langford said.
High winds can expand a window to the point of blowing out, he said. But considering Thursday’s mild winds, that was probably not the cause. Slight motion of the building can also exert stress on windowpanes of tall buildings, he said.
Check back for updates.
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