FREEPORT, Maine — Three people were sent to the hospital Tuesday when a water heater malfunction caused dangerous levels of carbon monoxide at a hotel, officials said.

Firefighters evacuated the Comfort Suites late Tuesday morning after a carbon monoxide detector found levels as high as 675 parts per million in one area of the hotel, officials said.

Two adults and a child were taken to a hospital after an initial evaluation by an ambulance crew revealed potential carbon monoxide poisoning. Their conditions weren’t not known.

Fire crews could have acted earlier. Someone from the hotel called a fire department business line on Monday and left a message after the carbon detector went off in a space near the water heater.

Anyone with concerns about carbon monoxide should dial 911, not leave a message, the fire chief said.