S/B I55 West of County Line Burr Ridge IL. The Tri-State Fire District was called at 4:12pm on November 18th for a report of a truck leaking an unknown product. Companies arrived to find a semi-tractor with box trailer and an unidentified liquid leaking from the front of the trailer. It was reported that the truck was transporting twelve 330 gallon vessels of a mixed load. Fire crews made a calculated recon of the trailer contents by entering in level B hazmat suits and SCBAs. It was determined that one of the protected vessels had rolled onto its side and ammonia chloride was visually leaking through the top port. Fire crews worked with the IL State Police, nine local fire agencies, and the mitigation team to secure the unit by offloading the product into another container then re-located the truck to an alternate safe area. No injuries were reported. The incident is currently under investigation. No more information is available at this time.