HILLSBORO, Ill. – Several people were sent to the hospital on Wednesday after overdosing at the Graham Correction Center in Hillsboro, Illinois.

One law enforcement official tells FOX 2 that a call went out to local agencies for all available NARCAN to be delivered to the facility, which is about an hour northeast of St. Louis.

Naomi Puzzello from the Illinois Department of Corrections said that a staff member at the Graham corrections facility was responding to a medical situation in which detainees seemed to be affected by an unknown substance.

Numerous staff members who responded to the incident were exposed to the substance. They were transported to a nearby hospital for treatment. Puzzello said other staff members who may have been exposed to the substance were also sent to a hospital.

The Hillsboro Area Hospital said it treated eight patients from Graham. St. Francis in Litchfield treated another nine patients from the facility.

A spokesperson from Hillsboro Area Hospital released the following statement: 

“Hillsboro Area Hospital has provided care to patients that have been transported from Graham Correctional Center. Hillsboro Area Hospital received eight patients. All patients are currently in stable condition and will continue to be monitored as needed. The initial 911 page was sent out around 2:38 p.m., and this is an ongoing situation. Hillsboro Area Hospital implemented our mass influx plan. All transported individuals were provided immediate care, including decontamination. The Hillsboro Hospital Administrative Team would like to thank our team members, Local EMS, Law Enforcement Officers, and County EMA for quick assistance.”

The detainees who were under the influence of the unknown drug were being treated at the Graham Correctional Center healthcare unit.

Hazmat crews with the Illinois State Police are investigating to determine the substance.

Additional details are limited at this moment. FOX 2 will give updates as more information becomes available.