Miami, FL – The Miami Herald – Hotel patrons at Miami Beach’s Wyndham Resort got a scare this morning when high levels of carbon monoxide were detected on its top four floors.

It all started when a family at the hotel on Collins Avenue began feeling nauseous with headaches. Fire crews responded, evacuating about 80 people. Nine people were taken to Mount Sinai with minor injuries.

Miami Beach fire chief Javier Otero told our news partners at CBS4 that the building is being ventilated.

”We know that it definitely was carbon monoxide. We don’t know the exact mechanism of how it happened … was it a leak in the exhaust system,” Otero told CBS4. “Was it simply gas building up in the roof because there was no wind, so it got picked up by the air intake system, so we’re looking at all the possibilites.”

Investigators say a gas-powered heater may be to blame.