Photo: The Canadian Press

Crew members on a dive boat say they were never instructed on emergency procedures before a fire swept through the vessel as it was anchored off the Southern California coast, killing 34 people as they slept below deck, according to federal documents released Wednesday.

National Transportation Safety Board investigators say the cause of the blaze aboard the Conception remains undetermined but a possible ignition point was phones and other electronics plugged into outlets. One crew member told investigators he saw sparks when he plugged in his cellphone hours before the fire.

The boat was carrying 33 passengers on a Labor Day weekend scuba diving expedition last year. The fire broke out on the final night as the Conception was anchored off Santa Cruz Island, about 25 miles south of Santa Barbara, the boat’s home port.

All of the passengers and one crew member sleeping below deck were killed — none apparently having a chance to escape. The other five crew members, including Capt. Jerry Boylan, survived by jumping into the water. They barely escaped after trying in vain to save the others, authorities said. Boylan made a mayday call at 3:14 a.m., saying, “I can’t breathe,” before abandoning ship.

They got into a nearby boat, whose captain kept calling for help as Conception crew members returned to search for survivors. It took more than hour after Boylan's first mayday call for the Coast Guard and other boats to arrive. The Conception sank just after daybreak.

Boylan could face federal manslaughter counts, and recent court documents say criminal charges are imminent. The NTSB has said all six crew members were asleep when the fire broke out, a violation of Coast Guard regulations requiring a roving watch.

Hundreds of pages of documents released by the safety board provide a detailed look at the boat’s final hours on Sept. 2, 2019. It will vote Oct. 20 on the investigation’s findings, as well as the blaze’s probable cause and any potential recommendations.

Ryan Sims, who had been working aboard the boat for just three weeks, told investigators he had asked the captain to discuss emergency plans the day before the fire. Boylan reportedly told him: “When we have time.”

“I didn’t know what the procedures were supposed to be,” Sims said. Other crew members also said they weren't familiar with safety procedures.

Sims told investigators he went to sleep after seeing sparks when he plugged in his cellphone, and the documents don't indicate that he reported what he saw. He told investigators that “while still in a sleep-like state, he had heard a pop and then a crackle downstairs” as another crew member yelled, “Fire! Fire!”

Sims, who broke his leg escaping the burning boat, has sued the vessel’s owners and the company that chartered it, alleging the Conception wasn't seaworthy and operated unsafely.

Families of 32 victims also have filed claims against the boat owners, Glen and Dana Fritzler, and the boat company, Truth Aquatics. In turn, the Fritzlers and the company have filed a legal claim to shield them from damages under a maritime law that limits liability for vessel owners. Court filings show they have offered to settle lawsuits with dozens of victims’ relatives.