Sgt. Todd Spencer says two other firefighters suffered minor injuries.
He says the firefighters were on the first floor of the Hampton Bays home when the floor collapsed and they fell into the basement.
He says four fire departments helped put out the blaze early Monday.
One firefighter suffered head injuries and burns, and another had burns to his head, neck and hands. The third firefighter's injuries were not immediately known. Spencer says none of the injuries are life-threatening.
The occupants of the house escaped unhurt.
The cause of the fire is under investigation.