(CN) — Federal transportation safety officials Tuesday could not definitively say what sparked a deadly California dive boat fire last year but faulted the operator for a lack of oversight that led to the tragedy that claimed 34 lives.
In the early morning of Sept. 2, 2019, ocean waves carrying the Conception boat were calm and winds brushed relatively gently against the Santa Cruz Island coast in Southern California.
The 75-foot commercial boat deployed as it had for decades, carrying 33 people aboard for a three-day scuba diving excursion.
A crew member noted the time, 2:15 a.m., as passengers and one crew member slept in the Conception’s lower deck.
Minutes later, a fire exploded, burning the fiberglass and plywood body of the vessel and filling it with smoke and flames that blocked fire hoses and the exits from sleeping quarters.
Five crew members sleeping in the upper deck later told authorities the smoke and flames forced them to abandon the boat and issue a distress call from a nearby vessel.
Nearly four hours after the fire erupted, the Conception was under 61 feet of water.
The National Transportation Safety Board investigated the incident and was set to vote Tuesday on a probable cause.
After a four hour virtual meeting, the five-member board could not definitively say what sparked the fire but said a number of factors made the incident more deadly.
The board faulted boat operator Truth Aquatics for not requiring a roving patrol, or night watchman, aboard the Conception, which investigators say allowed the fire to grow undetected in the rear of the main deck.
Board chairman Robert Sumwalt blasted the company for not following patrol requirements and other safety standards, including failing to give passengers timely safety briefings and not training crew members on emergency protocols.
“The captain thought having a deckhand sleeping in the bunkroom somehow fulfilled requirements for a roving patrol. Maybe that person would be sleepwalking,” Sumwalt said. “That’s the normalization of deviance.”
Investigator Andrew Ehlers told the board the U.S. Coast Guard doesn’t effectively enforce the roving patrol policy and “never” inspects vessels during overnight trips or when passengers are on board.
The Coast Guard hasn’t cited any vessel operator for not having a roving patrol since 1991 and has not proposed an enforcement plan since the Conception fire, Elhers said.
The NTSB investigation also found the Coast Guard lacks a requirement that smoke detectors be placed in all areas of commercial vessels.
The board voted Tuesday to recommend that all vessels with overnight accommodations install smoke detectors that can independently trigger system-wide alarms if a fire erupts in a certain area.
NTSB investigator Joseph Panagiotou told the board likely sources of the ignition are the Conception’s internal electrical system, charging stations plugged into power outlets, or improperly discarded cigarettes or other smoking materials.
Panagiotou said it’s common for passengers to leave cameras, headlamps and other devices plugged into charging stations all night.
A fire aboard the Truth Aquatics vessel Vision occurred months before Conception sank and was caused by sparks from a lithium battery that was charging.
The owner of the company told investigators he was not informed of the fire aboard the Vision.
Board member Jennifer Homendy said the lack of knowledge about the fire showed a breakdown in company oversight.
“I hate the term accident in this case because, in my opinion, it is not an accident if you fail to operate your company safely,” Homendy said.
NTSB investigator Adam Tucker said the probe ruled out weather conditions and illegal drug use by crew members as causes of the blaze.
Investigators told the board their access to Truth Aquatics’ internal records and staff was restricted shortly after the fire when local prosecutors decided to pursue criminal charges.
Board members said they were confident federal agencies involved in investigations would find ways to operate parallel probes.
“Once they’re done prosecuting, we still have a safety issue,” Homendy said.
The NTSB’s final, revised report will be released in the next few weeks.Crew members told investigators the blaze prevented them from reaching passengers in the lower deck, according to NTSB documents released Sep. 16.