OGUNQUIT, Maine (WHDH) -
Several people are recovering in Maine Sunday after a carbon monoxide leak at a hotel in Ogunquit.
Firefighters said the basement of the hotel had carbon monoxide levels that were 10 times what they should have been due to what they believe was the furnace.
They believe that the leak could have started as early as Saturday night.
Nine ambulances were sent to the InnSeason Resorts-The Falls on Route 1 where 21 guests got sick. Seven had to be taken to the hospital, but are now in stable condition.
The fire chief said that the building did not have carbon monoxide detectors, so officials are investigating whether the hotel was required to have them.
A law went into effect in August 2012 and the hotel could be grandfathered out of the law unless it had any renovations since that time.
"They should have carbon monoxide in the individual rooms as well as in the furnace room in the basement. The hotel was built approximately 25 years ago and at the time they weren't required to have carbon monoxide detectors," Chief Mark O'Brien said.