Daytona Beach, FL – WFTV – Some guests of a Daytona Beach hotel are out of the hospital after treatment for carbon monoxide poisoning. The problem was at the Plaza Ocean Club on Sunday.

Four guests and two workers were taken to hospitals after experiencing flu-like symptoms from the odorless, colorless gas.

As a precaution, the hotel told many guests to stay out of the building while firefighters searched for the gas leak.

“It’s not something we would have anticipated. Obviously, it’s never happened at this property before,” said Douglas Kosarek, senior vice president for Ocean Waters.

Firefighters discovered the leak was from the basement boiler and that the gas made its way up through an elevator shaft all the way to the top floor.