OGUNQUIT — Twenty-one people suffered carbon monoxide poisoning and seven of them had to be hospitalized following an incident Sunday at a Route 1 time-share resort that the fire chief said was not equipped with carbon monoxide detectors.

Fire Chief Mark O’Brien said tests at the resort detected highly elevated levels of carbon monoxide – 300 parts per million compared to 35 parts per million, the level that triggers carbon monoxide detectors to go off.

“These were extremely high levels,” O’Brien said Sunday night during a news conference outside the resort. “These were 10 times what the normal levels would have been. It’s very scary. We could potentially have had 21 deaths here.”

The affected building, one of four on the property, did not have any carbon monoxide detectors – an omission that might constitute a violation of state laws, the fire chief said.

Emergency crews from Ogunquit, Wells, Kennebunk, South Berwick and Sanford responded and evaluated 21 guests who had been staying at the InnSeason Resorts – The Falls at Ogunquit. The 77-unit resort, a complex of four two-story yellow and red brick buildings, is located at 639 Main St.

“Everyone had carbon monoxide in their bloodstream, and some of the levels made me very uncomfortable,” the fire chief added.

Three victims were taken to York Hospital. Four were transported to Southern Maine Health Care in Biddeford. All had been treated and released by early Sunday evening.

O’Brien said the resort contains time-share condominiums that are rented on a weekly basis. He said most of the affected guests were families on school vacation from Massachusetts or New Hampshire.

O’Brien said that some of the guests began feeling sick late Saturday night but thought they were suffering from food poisoning or had the flu. He said they reported feeling dizzy, lightheaded and nauseous.

Carbon monoxide poisoning can feel like the flu, but without a fever, according to the Maine Department of Health and Human Services. Symptoms may include headache, dizziness, fatigue, shortness of breath, nausea, vomiting and loss of consciousness.

A desk clerk at the resort alerted the Ogunquit Fire Department around noon Sunday after people staying in two different rooms complained of flu-like symptoms.

A preliminary investigation by O’Brien and the State Fire Marshal’s Office determined that the building’s gas furnace ventilation system, which is supposed to push carbon monoxide out of the building, malfunctioned, causing the potentially deadly gas to build up inside the building.

O’Brien said there were no carbon monoxide detectors in the affected building or any of the other three buildings at the resort. The affected building has been shut down and will be closed until at least Tuesday or Wednesday as state officials investigate whether the furnace was properly installed.

O’Brien and the State Fire Marshal’s Office have yet to determine whether the resort violated any laws.

State Fire Marshal Joe Thomas said Sunday night that a new state law requires any new single-family dwelling, hotel, motel, inn, bed and breakfast, fraternity or sorority house, and dormitory to have carbon monoxide detectors installed. The law, which became effective Aug. 1, 2012, also applies to any building that is converted or restored for any of those uses.

Thomas said the law contains a grandfather clause that allows homes or businesses that were constructed before 2012 not to have a detector installed.

He said the new law was developed after society became more cognizant of the dangers associated with carbon monoxide poisoning.

“The push (before 2012) was more on making sure everyone had smoke detectors,” Thomas said.

O’Brien said the Inn Season Resorts was built more than 20 years ago.

But he said the resort may have violated state law if it was renovated during that time. Investigators plan to check building permit records on Monday to determine if the facility has been remodeled.

“We believe it may have been grandfathered,” O’Brien said Sunday night. “As far as we know there haven’t been any renovations done to the property.”

O’Brien said more than 4,000 people from around the world belong to the homeowners association that uses the time share resort.

Reporters at the scene Sunday night were not allowed on the resort property. A woman who answered the phone at the resort Sunday afternoon said officials had no comment, The Associated Press reported. A desk clerk who answered the phone Sunday night referred all questions to the general manager, who was not available.

Dennis Hoey can be contacted at 791-6365 or at:

dhoey@pressherald.com

Beth Quimby can be contacted at 791-6363 or at:

bquimby@pressherald.com