WASHINGTON (AP) _ An arsonist may have started the fire aboard the Scandinavian Sea last year, and unorganized fire-fighting efforts rendered the $16 million cruise ship a total loss, federal officials say.

The National Transportation Safety Board announced its findings Tuesday in the investigation of the lingering fire that destroyed the Norwegian Caribbean Lines ship at Port Canaveral, Fla., March 8.

The ship, on a one-day gambling cruise-to-nowhere, returned to port and the 750 passengers on board escaped without injuries. The $16 million ship, however, was useless after the fire smoldered for nearly two days.

NTSB spokesman Brad Dunbar said the board concluded that the fire was caused by ''deliberate or accidental ignition'' of flammable liquids in a room belonging to one of the crew members.

Although the board refused to rule out the possibility that the fire could have been accidental, NTSB Chairman Jim Burnett said he suspects arson.

''An accelerant on the carpet was ignited and a rag soaked with alcohol was found in the waste basket,'' Burnett said. ''Given these circumstances, my personal opinion is that it was deliberate.''

Paul Esbensen, the board's marine accident investigator, said if the fire was set, investigators don't have a clue as to who was responsible.

The NTSB also noted that nobody seemed to know who was responsible for putting the blaze out. The board said negligence by the ship's captain, improper fire-fighting methods and a dispute over which agency was in charge of the operation contributed to the destruction of the ship.