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.

Lamb said the institution “might discover more” patients affected as its investigation continues.

“Based on what we learned about that report, we should have begun a more expedited process to investigate and consider immediate removal of Dr. Husel from patient care at that time,” Lamb said.

Husel was removed from patient care on November 21 and fired on December 5, the hospital said.

CNN has been unable to reach Husel, who worked for the hospital system for five years. He does not appear to have an attorney.

“On behalf of Mount Carmel and Trinity Health, our parent organization, we apologize for this tragedy, and we’re truly sorry for the additional grief this may cause these families,” Lamb said in a statement earlier this month. “Our team has contacted these families and will continue to answer their questions and concerns as best as we can.”

Lawsuit claims patient given lethal dose of fentanyl

Eight lawsuits have been filed by survivors of patients of Husel, naming him, the hospital system and others as defendants. The suits allege that excessive medication led directly to the patients’ deaths.

Several of the lawsuits claim that the drug fentanyl was prescribed in high doses.

One suit filed earlier this month by the daughter of Janet Kavanaugh says that the patient was given a lethal dose of fentanyl without her consent.

The complaint alleges that either the hospital’s medical records system failed to flag the high dosage as an error, or medical staff was alerted to the risks associated with the dose but “ignored the alerts because the order was intended to hasten the termination of Janet Kavanaugh’s life.”

Fentanyl is the deadliest drug in America, according to the Centers for Disease Control and Prevention.