MONTGOMERY COUNTY, Ill. – Authorities have closed down a stretch of northbound lanes on Interstate 55 near Litchfield, Illinois, after a semi-truck hauling hazardous materials overturned Saturday morning.

The semi-trailer appeared to be leaking gas after the rollover crash, according to a news release from Illinois’ Mutual Aid Box Alarm Hazardous Material Response Team.

“It was discovered that there were cylinders of a hazardous material present along with containers of paint and other non-hazardous items,” said the Illinois MABAS 56 Hazardous Materials Team in a news release.

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Illinois State Police also confirmed that truck hauling hazardous materials overturned around 8:30 a.m. Saturday. The crash happened near Milepost 52.

ISP says the lanes will be shut down for an “extended period of time.” Potential public safety impacts are unclear at this time, but drivers are still encouraged to find alternate routes before milepost 52. As of 3 p.m. Saturday, there is a back-up that’s several miles long.

This is a developing story. FOX 2 will update as more information becomes available.