UPDATE: The Placer County Sheriff's Office says the South Placer Jail booking area remains closed after several people were exposed to an unknown substance on Monday.

They said the booking area is being cleaned and the people affected have been released from the hospital.

They are expected to be okay.

Placer County Sheriff's Office says the substance was brought in by an inmate but they don't have any more details at this time.

They said it was originally thought to be Fentanyl, but the Roseville Fire's Hazmat Team ruled it out as a possibility.

Toxicology tests are being done to determine what the substance is.

This is a developing story.

Nineteen inmates and staff have been treated for exposure to an unidentified substance at a Northern California jail.

The Roseville Fire Department says it was called to the South Placer Jail northeast of Sacramento Monday afternoon by a report that an inmate was showing an "altered level of consciousness."

Officials say it's believed an inmate brought some unknown substance into the booking area.

Authorities say some inmates and sheriff's deputies had medical issues. Jaime Garrett with the Fire Department tells KTXL-TV that some felt disoriented, didn't know their names or where they were.

Six inmates and deputies were decontaminated and treated at the scene. Thirteen other people were decontaminated and sent to hospitals for evaluation.

Fire officials say the booking area was isolated and there's no threat to anyone else.

(Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)

The Placer County Sheriff's Office says several inmates at the South Placer Jail in Roseville are being treated for possible exposure to Fentanyl on Monday.

There is no word on how the exposure happened.

This is a developing story.