The general manager of Mitsubishi Heavy Industries Ltd.'s Nagasaki shipyard, where the Diamond Princess luxury liner caught fire last year, admitted Thursday that not all accidents during the ship's construction were reported.
Nobuyoshi Aikawa said at an inquiry he was only told about one of a series of suspicious small fires on the ship before the October blaze, which severely damaged the 113,000-ton liner.
The inquiry, held at the Nagasaki Regional Marine Accidents Inquiry Agency, was the first involving a fire on a ship under construction.
"Welding work on piping caused a steel plate in the ceiling to overheat and furniture in the room above caught fire," Aikawa said.
Workers are now required to report all accidents and abnormalities, and direct welding has been prohibited.
The board of directors of the inquiry agency, which acts as a prosecutor, concluded the fire merited an inquiry as it took place after the ship was launched.
The shipyard and four people, including the head engineer, were named as being involved in the incident.
During the inquiry, three judges and two academics serving as lay judges will try to determine the cause of the fire.
The blaze took place Oct. 1 last year, when furniture in Cabin 320 on the ship's No. 5 deck caught fire due to heat from welding work on the ceiling of the deck below. The ship was in the shipyard's main dock at the time.
The 14-deck vessel, 290 meters long and 41.5 meters wide, was designed to accommodate 3,100 passengers and is one of the world's largest luxury liners.
After the fire, the cruise ship was renamed the Sapphire Princess and it is expected to be completed next May. Its twin, which took the name Diamond Princess, was launched in April.