In a statement, the Rehabilitation Center Nursing Home said that as result of prolonged power failure due to Hurricane Irma, the home's transformer, which powered the air conditioning system broke down.
Elderly residents were evacuated Wednesday morning from the Rehabilitation Center at Hollywood Hills which lost power during the storm. Broward County said the home alerted officials Tuesday that it had lost power, but when asked if it had any medical needs or emergencies, it didn't request help.
A news release from the City of Hollywood said that three patients were found dead in the facility early Wednesday, while others were taken to the hospital and pronounced dead there.
Power outages also remain an issue in the Jacksonville area.
The Keys were largely evacuated by the time Irma barreled ashore as a Category 4 hurricane with sustained winds of up to 130 miles per hour (215 km/hour).
The nursing home's administrator, Jorge Carballo, said in a statement Wednesday evening that it was "cooperating fully with relevant authorities to investigate the circumstances that led to this unfortunate and tragic outcome".
Eight residents died at a Florida nursing home which has been without power since Hurricane Irma and the state governor vowed a full investigation Wednesday into what he called an "unfathomable" event.
Florida residents who evacuated ahead of the storm faced lengthy traffic jams, meanwhile, as they returned to check out their homes after days in shelters or with friends or family.
Police said a criminal investigation was underway. CEO Jacob Solomon said the group encouraged people to evacuate before the storm if they could, but now they're focused on helping them in their homes. Jon reports: "As of Tuesday, [the facility] was reporting that everything was OK, that they were using portable air conditioners and fans".More news: Man with knife attacks soldier in Paris
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The deaths come as Florida continues the recovery and rebuilding process days after Irma pounded the state's peninsula. The facility had no electrical power after Hurricane Irma struck the state on Sunday, officials said. "We have other patients in critical care", he said, though he didn't elaborate.
Officials initially said as many as 158 people had been moved from the center; on Thursday, police clarified that 145 patients were sent to Memorial Regional Hospital - 141 from the center and four from an adjoining facility.
The facility is not the only Florida nursing home that has been left without power by Irma.
The Rehabilitation Center of Hollywood Hills was incorporated in June 2015 and the hospital announced a year ago that it had purchased Palm Springs General Hospital in Hialeah for $40 million.
Count mayor Barbara Sharief has criticized the facility for being slow to react when its residents' health was in peril.
Popular with retirees, Florida is home to more than 680 nursing homes, which house about 73,000 residents, according to the Florida Health Care Association.
The Daytona Beach Fire Department said on Twitter a generator had been running inside the home.
In Green Cove Springs, on the St. John's River just south of Jacksonville, many families need a canoe to get to their front doors.
Police were checking on more than 40 other nursing facilities in Hollywood, Kate Stein of member station WLRN tells NPR's Newscast unit.