The captain of a scuba diving boat that caught fire and sank off the coast of California last year, killing 34 people who were trapped below deck, was indicted on US federal manslaughter charges for one of the deadliest maritime disasters in recent US history.

Jerry Boylan, 67, was charged with 34 counts of seaman’s manslaughter for “misconduct, negligence and inattention” by failing to train his crew, conduct fire drills and have a roving night watchman on the Conception when fire broke out September 2 2019, the indictment said.

“As a result of the alleged failures of Captain Boylan to follow well-established safety rules, a pleasant holiday dive trip turned into a hellish nightmare as passengers and one crew member found themselves trapped in a fiery bunkroom with no means of escape,” US attorney Nick Hanna said in a statement.

Boylan and four other crew members, who had all been sleeping, escaped from the flaming boat after he made a breathless mayday call.

All 33 passengers and one crew member perished in the bunkroom.

Some of the dead were found with their shoes on, leading to speculation they were trying to escape but were trapped by flames that blocked a stairwell and a small hatch that were the only exits to the deck above.

All died of smoke inhalation, according to coroner’s reports.

The rare federal charges against Boylan were brought under a pre-Civil War law aimed at holding steamboat captains and crew responsible for watery disasters that were far more frequent at the time.

Each count carries a possible 10-year prison term with conviction.

Federal prosecutors said they had informed Boylan’s lawyers of the indictment, and he was expected to surrender to federal authorities in the coming weeks.

His former defence lawyer, Michael Lipman, said they had expected the charges for more than a year.

Federal safety investigators faulted the owners of the vessel for a lack of oversight, but they were not charged with any crime, though the investigation is ongoing.

“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,” National Transportation Safety Board member Jennifer Homendy said at a hearing in October.

The company that owned the boat, Truth Aquatics Inc, has filed suit in federal court under a provision in maritime law to avoid payouts to the families of the victims.

The families of 32 victims have filed claims against boat owners Glen and Dana Fritzler and the company.

The cause of the fire has been under investigation for more there a year and may be impossible to pinpoint.

It began in an area on the main deck where divers had plugged in phones, flashlights and other items with combustible lithium ion batteries.

The fire happened on the final night of a three-day Labour Day weekend scuba diving excursion near Santa Cruz Island off Santa Barbara.

The 34 victims ranged from a new deckhand to scientists and engineers to parents with their teenage and adult children.

They came from as far away as China, Singapore and India.

Two passengers were celebrating birthdays.

The sole crew member who died, Allie Kurtz, 26, had previously worked as a cook on another Truth Aquatics boat and was thrilled with her promotion.

Her family said she loved the water and had childhood aspirations of becoming a pirate.

Marine biologist Kristy Finstad, who co-owned Worldwide Diving Adventures and chartered the Labour Day Weekend trip, first put on a dive tank at the age of nine and had done hundreds of dives in the rugged, windswept Channel Islands, off Santa Barbara’s coast.

Five members of the Quitasol family took the trip to celebrate their father’s birthday.

Sisters Angela, Nicole and Evan joined their father, Michael Quitasol, and their stepmother, Fernisa Sison.

The family had been scuba diving together for at least a decade.