A 20 vehicle pileup shutdown parts of I-57 Thursday afternoon near Peotone.
Some lanes are still blocked off as the cleanup and investigation begins.
State police say dense fog was to blame for the crash that happened in the northbound lane near Harlem Ave in Peotone around 5 p.m.
One northbound lane on between Wilminton-Peotone Road and Manhattan-Monee Road along with all southbound lanes reopened around 8:30 p.m.
Officials said there were multiple injuries but none appeared life-threatening.