HILLSBORO, Ill. (WCIA) — Hillsboro Chief of Police Randy Leetham confirmed there was an exposure to an unknown substance at the Graham Correctional Center on Wednesday.

He said the Illinois Department of Corrections is investigating the situation.

One law enforcement official told our sister station KTVI in St. Louis that a call went out to local agencies for all available NARCAN to be delivered to the facility.

This is a developing story.