The crash occurred shortly after 5 a.m.as two semi-trucks side-swiped each other on the southbound Tri-State Tollway near the Hinsdale Oasis.
One of the semi trucks was badly damaged with almost the entire right side of the truck being sheared off and debris was scattered over the two right lanes. Police said about two gallons of hydrochloric acid mixed with other chemicals began leaking from the truck, prompting the HazMat response.
LIVE TRAFFIC: Check out conditions on our live traffic map
At one point, all southbound lanes were closed. Shortly before 8:30 a.m., two of the lanes were reopened.
No injuries have been reported. The southbound Hinsdale Oasis parking lot has been evacuated, police said.