Bonhomme Richard is ‘survivable,’ though Navy official is unsure it will be repaired after fires burned ship

A blaze that engulfed the San Diego-based amphibious assault ship Bonhomme Richard for more than four days was extinguished Thursday, Navy officials announced.

What is still unknown about one of the worst noncombat Naval fires is its cause, the extent of the damage and whether and when the ship might be repaired. An investigation is expected to take weeks.

Rear Adm. Philip Sobeck, commander of Expeditionary Strike Group 3, said in an emailed statement Thursday that the cause of the fire is unknown.

He has said a spark from an unknown source could have ignited heavy-duty cardboard boxes, rags and other maintenance supplies that were being stored in the lower vehicle storage area. The fire then traveled upward to the well deck — a wide hangar-like area — and took off from there, Navy officials have said.

“We did not know the origin of the fire,” Sobeck said Thursday in a statement.

“We do not know the extent of the damage. Our fire teams are investigating every space to verify the absence of fire. Until every space is checked and there are no active fires we will not be able to commence any official investigations.

“What we do know is that brave sailors from commands all across San Diego worked tirelessly alongside federal firefighters to get this fire extinguished and I want to thank them for their efforts.”

Sobeck said 40 sailors and 23 civilians were treated for minor injuries such as smoke inhalation and heat exhaustion during the roughly 100-hour long firefight.

The fire on the 844-foot ship began about 8:30 a.m. Sunday and sent acrid plumes of smoke into the San Diego skies for two days. By Tuesday morning, the plume was noticeably smaller, although the smell of the fire stayed in neighborhoods nearest the base through Thursday.

Firefighting crews from a dozen San Diego-based ships — more than 400 sailors — assisted federal firefighters from bases throughout Southern California at combating the fire. Navy helicopters from Helicopter Sea Combat Squadron 3 dumped more than 1,500 buckets of water on the ship around the clock.

Tugboats also shot water onto the ship to cool the hull.

At the height of the conflagration, temperatures onboard reached 1,000 degrees.

Several photos of the damage to the ship’s island superstructure and interior were posted online over the last two days, showing entire spaces blackened by fire and smoke, as well as at least two large holes in the island’s roof. The forward mast — located on the island — collapsed early Monday.

Navy officials have not commented on the damage in the online photos, nor have they released any photos of damage.

Wednesday night, the Bonhomme Richard shifted and listed toward the pier, prompting the Navy to pull off firefighting sailors searching the bowels of the warship for remaining hot spots.

The withdrawal of the roughly 30 sailors was out of an abundance of caution; there was no fear that the 840-foot ship would capsize, Lt. Cmdr. Patricia Kreuzberger said. Crews went back on the ship within an hour.

Schwegman said Wednesday that 84 sailors who lived on the Bonhomme Richard full time have been moved to living quarters on Naval Base San Diego. The crew’s living quarters were lost in the fire.

Dyer writes for the San Diego Union-Tribune. The Associated Press contributed to this report.