Flames raged for hours on Sunday aboard a U.S. warship docked at Naval Base San Diego, sending 21 people to the hospital with minor injuries and prompting a relocation of two other Navy vessels moored nearby, military and local fire officials said.
The San Diego Fire-Rescue Department reported an explosion in conjunction with the blaze, which broke out at about 8:30 a.m. local time (1530 GMT) aboard the USS Bonhomme Richard, an amphibious assault vessel in port for routine maintenance.
The blast was believed to have been triggered by the rapid initial release of heat from a confined space under pressure, as opposed to an explosion of fuel or ordnance, Rear Admiral Philip Sobeck told a news conference on Sunday evening.
While the precise source of the blaze was unknown, the fire originated in a lower cargo hold of the ship and spread into the decks above it, consuming materials that typically burn in an office or apartment fire, Sobeck said.
Navy spokesman Mike Raney told Reuters there was no immediate evidence of foul play.
Ammunition normally carried aboard warships at sea had already been unloaded as a standard safety precaution before the vessel was placed into maintenance, Navy officials said.
Roughly 1 million gallons of fuel remained isolated “well below where any heat source is,” and fire crews worked all day to “make sure that’s not affected,” the admiral said.
Palls of thick, acrid smoke visible for miles around the base engulfed much of the 844-foot (257 meter) warship for several hours, as about half a dozen firefighting boats in the harbor trained streams of water onto the burning vessel.
Seventeen sailors and four civilians were taken to local hospitals for treatment of non-life-threatening injuries, and all those who were aboard the warship - about 160 personnel - were accounted for, the Navy said in a statement.
Sobeck said the hospitalized sailors were all listed in stable condition. Navy officials said the injuries consisted mainly of smoke inhalation, heat exhaustion and minor burns. The vessel normally carries a crew of roughly 1,000.