(CNN) Three more employees have been placed on leave at a Columbus, Ohio hospital where a doctor is alleged to have overprescribed pain medicine.

"We have now placed 23 colleagues on administrative leave, including members of the management team," Mount Carmel Hospital spokesperson Samantha Irons said.

At least 34 near-death patients received excessive doses of pain medication at Mount Carmel while under the care of Dr. William Husel, the hospital's President and CEO Ed Lamb said in a statement last week. All 34 patients are deceased, a hospital spokesperson said.

Of those 34, 28 patients received excessive and potentially fatal doses of medication, the hospital said. Six received excessive doses that went beyond providing comfort but that were not believed to be the cause of their deaths, according to the hospital.

Three of the patients died after the hospital system received a report related to the doctor's care, the hospital said.