Pennsylvania ordered a lockdown Wednesday of its entire state prison system after a number of staffers became ill from suspected exposure to tainted synthetic drugs, an incident that comes as five inmates have died from overdoses in Arkansas and dozens were sickened in Ohio under similar circumstances.State Corrections Secretary John Wetzel said the cautionary move was aimed at ensuring the "safety and security of our employees" after multiple illnesses among prison staff in recent weeks."Our state prisons, especially those in the western part of the state, have experienced recent incidents in which employees have been sickened and we need to get to the bottom of this issue now," Wetzel said. The state's 21 prisons will remain closed to visitors indefinitely, and most mail service throughout the system has been frozen, according to The Associated Press.Since Aug. 6, 29 employees have become sick in 13 separate incidents throughout the Pennsylvania prison system, and that's not counting inmates who have also become ill."This weekend was kind of rough. The last couple of days we even had a couple more incidents. So, the secretary said, 'That's it, lock it down,' " Corrections spokeswoman McNaughton tells NPR.That means no inmates will be moved, she said. "They're not going to leave their housing unit to go to programs. They're not going to leave their housing unit to go to education or to eat their meals. Everything is going to happen in their cells," McNaughton says.So far, only synthetic cannabinoid — known as K2 or spice — has been connected to the string of illnesses in Pennsylvania, McNaughton said. The order to close off Pennsylvania's prisons to the outside world came hours after Ohio reported that more than two dozen people were treated for possible exposure to what officials there believe is the powerful opioid fentanyl.Also on Wednesday, in Arkansas, two inmates in a maximum-security prison were found dead, bringing the number of suspected drug-related deaths at the facility this week there to five, according to the state's Department of Correction.Arkansas officials have not confirmed the cause of death for the five inmates at the Varner Unit this week, but Reuters, citing the Department of Correction, reports thattainted illicit drugs are suspected.Reuters notes, "Arkansas prisons have struggled for months to halt the use of synthetic forms of marijuana, which have been linked to numerous deaths."Prison officials told Reuters that there were about 1,000 overdose cases in 2017. And KATV reported drug-related deaths within Arkansas state prisons this year could surpass last year's numbers: