The sheriff's office said it was possible the man was pushed down the shaft at the construction site.
At least three people died after a bridge set to be demolished collapsed.
The explosion happened as work was being done to install a new floor in the basement of a home in the 1600 block of West Winona Street, Chicago police said.
After the crane crushed her car, the woman seemed astonished to be able to say "absolutely nothing" when asked what hurts.
Lawsuits for the deceased worker and another worker who was injured are asking for millions of dollars in damages from the general contractor Turner Construction, as well as one of the sub contractors, Adjustable Forms Incorporated.
A lawsuit filed by the family of another worker who was injured in the same collapse alleged the workers had complained about the stability of that corner days earlier, when the scaffold was lower to the ground.