Updated

A Florida nursing home where 12 elderly patients died of overheating after Hurricane Irma knocked out its air conditioning made matters worse by using portable units that were not properly ventilated and increased temperatures in most of the facility, an engineer testified in a deposition.

William Crawford, an air-conditioning engineer, said in a deposition released by the state late Thursday that the Rehabilitation Center at Hollywood Hills didn't have nearly enough portable units and those they had wound up heating much of the facility because they were not being vented to the outside. The 150-patient home is suing the state to get its license reinstated and Crawford has been hired by the state as an expert witness.

Crawford told the home's attorney Geoff Smith in a deposition last month that the nine portable air conditioners the home deployed after September's storm were insufficient, producing only about 10 percent of the cooling capacity of the home's central cooler. Authorities say temperatures in the home rose dangerously between Sept. 10, when Irma knocked out the home's air conditioner, and Sept. 13, when patients began dying and the facility was evacuated. Under state law, nursing homes must maintain a temperature of 81 degrees (27 degrees Celsius) or less.

"The capacity of the spot coolers was insufficient to cool the space of the patient areas," Crawford said.

Air conditioners work by removing heat from an enclosed space and taking it outside. Crawford said the heat from the portable air conditioners on the first floor was being vented into its ceiling, trapping it beneath the second floor. That meant that most of the first floor's heat was rising to the second floor, with some flowing back to the first floor. He said conservatively the temperature in the cavity between the first-floor ceiling and the second floor was at least 95 degrees (35 Celsius) but probably reached between 100 degrees and 110 degrees (38 to 43 Celsius).

He said without proper ventilation, the heat generated by the air conditioners' operation actually increased temperatures inside the building, although he couldn't say exactly how hot it got.

"I can say with certainty it was above 81" in most of the facility, he said. It's possible, he said, that the temperature was cooler within 9 feet (3 meters) of the five portable units that were on the first floor. "There was no way they maintained 81 degrees on the second floor," where four units were deployed, he said.

Julie Allison, an attorney for the home, said in a statement Friday, "We will be addressing these matters in court, and we look forward to sharing all of the evidence that has been obtained and that will be considered in a fair and impartial manner by the judge."

Smith wrote in a letter to Congress in November that during the outage, staff monitored patients and none exhibited any sign of heat exhaustion the first two days.

He said about 3 a.m. on Sept. 13, several patients began showing signs of respiratory and cardiac distress. He said the staff summoned paramedics for each patient and followed proper protocols.

"The onset of heat stroke is impossible to predict and can occur in 10 to 15 minutes," he said. He said the elderly are susceptible at 81 degrees (27 degrees Celsius).

The 12 deaths have been ruled homicides but no one has been charged. A criminal investigation is ongoing.