One of the trucks lost its container that fits on top of the flatbed. It tipped over onto the other vehicle. It reportedly happened after a side-swipe accident, which caused the load to tip up and made it too tall to fit under the 14-foot Hubbard St. Bridge.
There was a fuel leak involved as well. Firefighters, IDOT and Illinoiois State Police were on scene.
All lanes were closed for about an hour. Some lanes reopened around 6 p.m. The expressway was backed up as far as O'Hare at its height.
There were no early reports of injuries.