Photo: Contributed

Eight patients at a sweltering nursing home died after Hurricane Irma knocked out the air conditioning, raising fears Wednesday about the safety of Florida's 4 million senior citizens amid power outages that could last for days.

Hollywood Police Chief Tom Sanchez said investigators believe the deaths at the Rehabilitation Center at Hollywood Hills were heat-related, and added: "The building has been sealed off and we are conducting a criminal investigation."

Gov. Rick Scott called on Florida emergency workers to immediately check on all nursing homes to make sure patients are safe, and he vowed to punish anyone found culpable in the deaths.

"This situation is unfathomable," he said.

The home said in a statement that the hurricane had knocked out a transformer that powered the AC.

The five women and three men ranged in age from 70 to 99.

Exactly how the deaths happened was under investigation, with Sanchez saying authorities have not ruled anything out, including carbon monoxide poisoning from generators. He also said investigators will look into how many windows were open.

Across the street from the stifling nursing home sat a fully air-conditioned hospital, Memorial Regional.

Broward County said the nursing home had alerted the county emergency operations centre on Tuesday that it had lost power, but when asked if it had any medical needs or emergencies, it did not request help.

"It's a sad state of affairs," the police chief said. "We all have elderly people in facilities, and we all know we depend on those people in those facilities to care for a vulnerable elderly population."

When asked why the patients hadn't been taken across the street to Memorial Regional hospital when temperatures became dangerous, Hollywood city spokeswoman Rayelin Storey said, "We can't get inside the heads of the staff and the administrators of this facility."