From the Illinois State Police:
Update: As of 9:55 PM, Southbound lanes continue to remain closed due to the vehicle fire. The fire is being difficult to extinguish due to the semi trailer being loaded with produce. They say the truck tractor was not involved in the fire. Traffic along I-57 southbound in being diverted off the interstate and onto US 45 at Paxton, Exit 261.
As of 9:00 PM, Illinois State Police and Fire Department Personnel are on scene with a semi trailer fire on I-57. The incident occurred southbound near milepost 255. At this time southbound lanes are currently closed. Please seek an alternate route and avoid the area for the time being.