GRAFTON, Ohio (WJW) — Eight people were taken to the hospital Saturday afternoon after a man incarcerated at Lorain Correctional Institution was found unresponsive in his cell and staff members tried to help, the Ohio Department of Rehabilitation and Correction (ODRC) confirmed to FOX 8.

A medical team was able to revive the man after giving him Narcan and he was taken to the hospital. However, then seven of the people on scene began “exhibiting various symptoms,” ODRC said, and they were all rushed to the hospital.

The prison staff members were said to be responsive at the time they went to the hospital and all have reportedly been released.

ODRC said they are still not sure what caused the medical symptoms but a “hazardous substance” has not been ruled out. An investigation is underway, which included some donning hazmat suits.

Following the incident, everyone in that area was relocated and it’s been secured.