HARRISBURG, Pa. (AP) -- Pennsylvania's state prisons are on lockdown after staff members at a fourth prison required treatment in recent weeks from exposure to a yet-unidentified substance described as a liquid synthetic drug.
The Department of Corrections announced the step Wednesday, a couple hours after it reported that two guards and three nurses at Albion state prison reported feeling sick and required medical attention.
The department didn't say how long the lockdown will last.
In the meantime, it's suspending prison visits, closing mailrooms to non-legal mail and requiring all employees to use gloves and other protective equipment.
Pennsylvania previously reported five separate cases between Aug. 6 and Aug. 13 in which 18 employees in three other western Pennsylvania prisons showed symptoms that required medical treatment.
Prison staff also is to use extra caution with parole violators and newly arrived inmates.