COLUMBUS, Ohio — An intensive care doctor ordered "significantly excessive and potentially fatal" doses of pain medicine for at least 27 near-death patients in the past few years after families asked that lifesaving measures be stopped, an Ohio hospital system announced after being sued by a family alleging an improper dose of fentanyl actively hastened the death of one of those patients.

The Columbus-area Mount Carmel Health System acknowledged the doses were larger than needed to provide comfort for dying patients. That raises questions about whether there was an intentional or possibly illegal use of the drugs to accelerate deaths.

The system said it has fired the doctor, reported findings of an internal investigation to authorities and removed 20 employees from patient care pending further investigation, including nurses who administered the medication as well as pharmacists.

Mount Carmel said the situation came to light because an employee reported a safety concern. The health system shared no information about what might have prompted employees to approve and administer the excessive dosages.

"Regardless of the reason the actions were taken, we take responsibility for the fact that the processes in place were not sufficient to prevent these actions from happening," Mount Carmel President and CEO Ed Lamb said in a video statement . "We're doing everything to understand how this happened and what we need to do to ensure that it never happens again."

The attorney who brought the lawsuit said, in that case, either layers of safeguards repeatedly failed to flag a "grossly excessive" dosage of fentanyl, or the medical professionals intended to accelerate the death of the patient, 79-year-old Janet Kavanaugh.

"On balance, it's hard to believe the former occurred rather than the latter. ... This is not just a simple situation of an error," lawyer Gerry Leeseberg said Tuesday.

The lawsuit was filed Monday in Franklin County against the health system, a pharmacist, a nurse and the doctor, whom it identifies as William Husel.

Dr William Husel WCMH

Case records listed no attorney yet to comment on Husel's behalf. There is no public personal phone listing for him, and other numbers linked to him weren't accepting calls Tuesday.

Husel's case emerges amid a national debate over physician-assisted death. In such cases, physicians prescribe medications in life-ending amounts to terminally ill patients.

Five states — California, Oregon, Vermont, Washington and Colorado — allow the practice, and 20 have considered but not passed legislation to do so, according to the nonpartisan National Conference of State Legislatures. A Montana court also legalized it there, though there's no regulatory framework in place. In Ohio, the practice remains illegal. A bill that would have allowed terminally ill, mentally competent patients to self-administer a prescription to end their lives failed to gain traction in the last legislative session.

But Joe Carrese, a faculty member at the Johns Hopkins Berman Institute of Bioethics, said that such laws are carefully crafted. He said that if Husel administered lethal quantities of drugs to unwitting patients in order to end their lives, his acts didn't meet the definition of physician-assisted death.

"In this case, if that was the intent, this was essentially euthanasia, which is not legal anywhere in the United States and not at all the same as physician-assisted death," he said.

Franklin County Prosecutor Ron O'Brien confirmed that his office has met with doctors, hospital executives and attorneys and that an investigation is underway, but he wouldn't discuss details. He said they've received cooperation from Mount Carmel, which operates four hospitals around Columbus, and from parent organization Trinity Health, one of the country's largest Roman Catholic health care systems.

Records show the State Medical Board in Ohio has never taken disciplinary action against Husel. It's unclear whether that board ever received a complaint or conducted an investigation about him, as such records are confidential under Ohio law, and outcomes are made public only if the board takes formal action.

Husel was a supervised resident at the Cleveland Clinic from 2008 to 2013, according to a statement from the medical center. It's now conducting an internal investigation of his work, but it said a preliminary review found that his prescribing practices were "consistent with appropriate care provided to patients in the intensive care unit."

Carrese, from the bioethics institute, commended Mount Carmel for encouraging a culture in which medical staff and other employees can come forward without fear, but he said the extent of the allegations is concerning.

"The fact that there may be other patients, up to 26 other patients, really calls into question whether the culture of safety and reporting that they're shooting for, whether there's more work that needs to be done," he said.

The allegations carry echoes of prior Ohio cases in which patients were killed.

Nurse's aide Donald Harvey, dubbed "the Angel of Death," claimed responsibility for killing more than 50 people in Cincinnati and Kentucky hospitals during the 1970s and '80s, mostly by poisoning. Many were chronically ill patients, and Harvey claimed he was trying to end their suffering.

Admitted serial killer Michael Swango, the former physician dubbed "Dr. Death," pleaded guilty to killing four people, including one while interning at an Ohio State University hospital, and was believed to have poisoned dozens as he moved between hospitals in various places.

Leeseberg, the attorney in the Mount Carmel lawsuit, said an important difference in this case is that multiple people were involved in the patients receiving the drugs.

"The pharmacist has an obligation to question an order, and the nurse has an obligation to question the order as well," Leeseberg said. "All of those safeguards were overridden or ignored. It's like nothing I've ever seen."