(CBS) — All lanes on the southbound Tri-State have been closed after an accident involving two semis.

Illinois State Police says crews are working to open all but two lanes so traffic can start moving again.

The crash happened around 5 a.m. when two semis collided on the southbound Tri-State near the Hinsdale Oasis.

One the the trucks was carrying hydrochloric acid and other chemicals, which resulted in a hazardous materials response. The side of one of the semis was completely shredded.

The southbound Hinsdale Oasis parking lot has also been evacuated.

Backups in the southbound lanes stretched for at least four miles.