Durham, N.C. — Federal officials are investigating a long-term care facility within Durham Regional Hospital following a fatal fire last month, officials said Thursday.

The Nov. 6 fire started during a defibrillation procedure at Select Specialty Hospital, a separate facility that specializes in long-term acute care and occupies the sixth floor of Durham Regional. One patient died, and three employees were treated for smoke inhalation.

The federal Centers for Medicare and Medicaid Services launched an investigation into Select Specialty and found evidence of a practice that posed immediate jeopardy to patients' health and safety.

A Nov. 29 letter from CMS to Chief Executive Robert Jernigan said that, while that problem was quickly corrected, investigators also found deficiencies relating to its governance, patient rights and nursing services.

Federal policy prohibits the agency from revealing what those deficiencies are until the final report is complete, which officials said could take another month or so.

Select Specialty, which couldn't be reached for comment Thursday, would have to draw up a plan to address the deficiencies and obtain federal approval of it.

Fire investigators have determined the fire was an accident, but they haven't pinpointed how it started.