Warden Joe DeMore said the six Butler County Prison staffers sent to the Butler Memorial Hospital's emergency room Tuesday night have all returned to duty.

“They were released from the hospital around 10:30 last night,” DeMore said. “They're cleared to come back to work.”

The hospital staff followed its plan well in Friday's incident, according to Dr. Dave Rottinghaus, emergency department director.

Rottinghaus said the response was part of the prepared mass casualty or disaster plan.

“Depending on what's happening, we have certain responses prepared,” he said.

Rottinghaus said the four correctional officers and two nurses transported Tuesday night were confined to the ambulance receiving bay.

“We can wall that off and do our decontamination in that space,” he said. “That's how we really minimize the risk of contamination.”

Rottinghaus said the staff treating the confined patients were properly attired.

“The staff put on gear to prevent inhaling the substance, whatever it may be,” he said. “They made sure that their eyes and mucus membranes and other parts of their body were covered.”

DeMore said the investigation is ongoing.

He said the Butler County Hazmat Team was at the prison for a couple hours but did not find residue of any substance. He said both the cell and the medical ward were decontaminated, but the substance still has not been identified.

DeMore said the Hazmat team is taking care of lab work regarding anything they found in the prison or medical bay.

DeMore said the hospital drew blood samples and was running tests trying to identify the substance, but he's not sure what the timetable for its completion is or if they'll find anything.

“Some of the synthetic stuff, they can't get confirmed positive tests,” DeMore said.

Jana Panther, director of marketing and public relations for Butler Health System, said tests of that nature could take a couple of weeks to produce results.

DeMore said his officers followed appropriate search and seizure procedures, including the wearing of gloves. He said the officers were in the middle of seizing items by placing them in bags when they started feeling symptoms of elevated heart rates and dizziness.

DeMore said it is too early to say how the original three officers came into contact with the substance. He said it is also unclear how the fourth officer that helped get his comrades to the medical bay and the two nurses got sick.

“They were exposed to the three that were already suffering from symptoms,” DeMore said.

He said their search and seizure procedures will be reviewed.

“We're taking into consideration some different means to equip the officers with masks and stuff like that if we have information of contraband or things like that,” DeMore said.

He said he is just glad everyone has recovered and returned to duty.

“That's a big relief,” DeMore said. “My No. 1 priority here is to ensure safety for our staff and inmates.”