HILLSBORO, Ill. – Authorities say two suspicious substances at the center of a high-profile investigation Wednesday in rural Illinois are nonhazardous.

At least 17 staff members hospitalized from the situation Wednesday have been treated and released as of Thursday, a spokesperson from the Illinois Department of Corrections tells FOX 2.

The situation was previously referred to as a possible mass overdose at the Graham Correctional Center in Hillsboro, Illinois. During the afternoon houts, local law enforcement agencies were asked to deliver all available NARCAN to the facility, which is about an hour northeast of St. Louis.

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

While responding, some staff members reported feeling dizzy. The Illinois Department of Corrections says those staff members were sent to a hospital “in an abundance of caution” for observation and treatment. The Hillsboro Area Hospital said it treated eight patients from Graham. St. Francis in Litchfield treated another nine patients from the facility.

Hazmat crews with the Illinois State Police investigated to determine the suspicious substances. According to ISP, the substances were identified as acetaminophen and paracetamol in nasal spray and aluminum phosphate, ethylpyrrole, and benzene in baby powder.

“The substances were identified as nonhazardous and should not have necessitated the use of Narcan or required hospitalization, but IDOC works diligently to ensure the safety of both incarcerated individuals and employees and worked swiftly to ensure everyone had access to the care they requested,” said Puzzello in a statement Thursday.

ISP says no one in custody required hospitalization. ISP is conducted additional testing on clothing items Thursday, and tests came back negative for life-threatening substances.