CHICAGO (WLS) -- A fifth car has been discovered in the wreckage after five vehicles, including two semis, caught fire in a large crash on the city's Southwest Side.At least one person was found dead in the fifth vehicle - a minivan. That person's identity has not been released.The other four drivers managed to escape the crash on the Stevenson Expressway just east of Cicero Avenue. The expressway was closed in both directions at the crash site for nearly three hours. All lanes of northbound I-55 were reopened by 4 p.m. Southbound I-55 reopened around 12:05 a.m. Tuesday, nearly 14 hours after the crash.Illinois State Police said the two trucks collided on outbound I-55 near Cicero around 10:50 a.m. Monday. All of the vehicles appeared to be fully engulfed by flames, and thick, black smoke could be seen for miles.The fire department upgraded the blaze to a two-alarm around 11:25 a.m. State police said one of the semis was hauling a hazardous material - 17,800 lbs. of paint. The other was carrying 40,000 lbs. of frozen meat. A Level 1 hazmat response was called. CFD dispatched a foam truck from Midway International Airport to help put out the flames. The fire was extinguished by around 11:55 a.m.After the fire was struck, an EMS Plan 1 was called, which sends five ambulances to the scene.All three cars were destroyed by fire. State police are investigating whether the cars were involved in the original crash or if they were collateral damage.Traffic on I-55 was backed up for miles in both directions Monday. Drivers were advised to seek alternate routes.No sooner did the crash take place than the tanker truck of paint burst into flames. The materials spilled, spreading the fire onto four other vehicles, including a second semi.Just getting the right emergency equipment on site to fight the fire proved a challenge."We're concerned about flammable liquids, there's corrosives. We had to regroup, back off, get the proper equipment," said Asst. Deputy Cmsr. Timothy Sampey, CFD. "So we had to stop the traffic in both directions as well as the runoff of the flammable liquid coming towards the traffic stuck in traffic - a lot of things to juggle at first."The drivers of both trucks were unharmed. One person in a passenger car was taken to the hospital in stable condition, but it wasn't until the fire was struck and a search conducted that a body, inside a minivan stuck underneath the first semi, was discovered."It's going to take some time for our investigators to determine exactly what happened. Review all the parties that were involved, all the drivers and passengers if applicable to find out exactly what happened," said Master Sgt. Jason Bradley, ISP.