SAN JUAN, Puerto Rico (AP) ? Combustible materials used in the construction of balconies on the Bermuda-registered cruise ship played a major role in the quick spread of a fire that killed an American man and injured 13 passengers, a British marine agency said yesterday.

The Marine Accident Investigation Branch, which examines accidents on British ships, issued a report in connection with the fire that broke out on the cruise ship while it sailed from Grand Cayman to Montego Bay, Jamaica, on March 23.

The cause of the fire has not been determined, but the agency warned that a type of widely used plastic called polycarbonate found in the ship?s balconies was highly combustible. It recommended stepped up vigilance by crews, such as lookouts and additional fire patrols. Stephen Meyer, the British agency?s chief, said fires such as the one were ?extremely rare? and he believed the cruise industry had identified measures to prevent similar accidents. Princess Cruises, which operates , said they are implementing the British agency?s recommendations, noting they have put into place a 24-hour fire watch of the balconies, will remove combustible materials from the balconies, and introduce fire detection and suppression systems.

?We want to assure our passengers that, with these measures in place, they can feel confident that their safety and well being aboard our ships is not compromised,? the company said in a statement.