Three Bureau of Prisons staff members at the Federal Corrections Insititute in Manchester were hospitalized Monday.

Officials say the staff members were all working in or near the facility's mail room when they began feeling ill.

We learned from 911 audio that those symptoms included nausea, dizziness, elevated heartbeat and blood pressure, and numbness in the lips and tongue.

"They had three of their guards who got symptomatic after they thought they had been exposed to something, we didn't know what," said Doug Baker, Chief of Somerset-Pulaski County Special Response Team, State Regional HAZMAT 12. "Long story short it was a long night everything ended well, everybody's home safe."

In a release from the Federal Bureau of prisons, officials say HAZMAT teams were dispatched to test the area and "determine whether a biological type substance may be present."

It's not yet known what caused the apparent illness. We do not know the conditions of the staff members.

The prison, which houses around one thousand offenders, is under "modified operations."

People who live nearby the prison tell us they were not scared, but they did worry for the workers in the mail room.

"Hopefully they won't have no aftereffects from the chemical or whatever they've gotten in," said Bobby Jones, who lives down the road from the prison.

Here's the full release from the U.S. Department of Justice: