The National Transportation Safety Board issued a final report on the September 2015 fire aboard the Carnival Liberty, pinning the blame on engine bolts that had been insufficiently tightened.
The fire occurred while the Carnival Cruise Line ship was docked in Charlotte Amalie in the U.S. Virgin Islands on Sept. 7. It led to a precautionary evacuation of the ship.
In its report, the board said it found loose bolts on a flange that held a fuel intake line to one of the diesel generators, probably because of improper tightening during maintenance and pipe vibration over time. That triggered an uncontrolled fuel spray from the connection onto a hot part of the engine.
Because the ship was in port and many passengers were ashore, there was confusion in tracking how many people were evacuated.
The report recommends that Carnival better train the crew in the use of the water-based fire extinguishing gear in the engine room. It also said Carnival should establish or improve its procedures for accounting for persons aboard in a mass evacuation in port.