The 34 victims in a scuba boat fire off the coast of California last year died as a result of carbon monoxide poisoning, according to authorities on Thursday.

The Santa Barbara County coroner's reports listed smoke inhalation as the cause of death for all 33 scuba divers and one crew member who died in the fire that broke out aboard the Conception on Sept. 2, 2019. Their deaths were considered accidental, police said.

CALIFORNIA DIVE BOAT OWNERS FILE LAWSUIT TO AVOID LIABILITY AFTER DEADLY FIRE

Firefighters respond to a fire aboard the Conception dive boat in the Santa Barbara Channel off the coast of Southern California on Sept. 2, 2019. (Santa Barbara County Fire Department via AP, File)

The blaze occurred just after 3 a.m., and swept through the boat anchored off Santa Cruz Island for a three-day excursion over Labor Day Weekend. The only survivors were those asleep above deck, which included the captain and four other crew members.

Descriptions of the bodies in the report noted some were wearing clothes and shoes, while two were found to have held a cellphone and flashlight, according to Lt. Erik Raney of the Santa Barbara County Sheriff's Office.

All of the victims were found out of their bunks, hinting they could have been attempted to escape, although he added there was no way to determine if they were trying to do so. Some were found on the surface of the water, while others inside the boat's hull, or on the ocean floor after it capsized.

A number of the victim's families have since filed wrongful-death claims against the Santa Barbara-based operator of the vessel, Truth Aquatics, which is owned by Glen and Dana Fritzler, according to the Santa Barbara Independent.

CALIFORNIA DIVE BOAT IN LABOR DAY FIRE WAS EXEMPT FROM COAST GUARD SAFETY REGULATIONS: REPORT

In 1996, the Coast Guard implemented a set of standards on new vessels, requiring escape hatches at least 32 inches wide and illuminated exit signs. The 75-foot vessel, built-in 1981, had a 24-inch hatch and no illuminated signs

The burned hull of the dive boat Conception is brought to the surface by a salvage team in the Santa Barbara Channel off Santa Cruz Island in Southern California on Sept. 12, 2019. (Brian van der Brug/Los Angeles Times via AP, File)

An official from the National Transportation Safety Board remarked how difficult it was to reach an escape hatch in the bunk room, which was a design that routinely met regulations. The boat reportedly passed its two most recent safety inspections, according to Coast Guard records.

The survivors said they woke to find the boat in flames. They were unable to reach the sleeping passengers and had to jump in the water to save their own lives.

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Raney told The Associated Press the coroner’s office did not do internal autopsies of the bodies. He said external examinations of the victims and black soot in their trachea, as well as toxicology tests, showed enough evidence of smoke inhalation and carbon monoxide poisoning to avoid autopsies.

Fox News' Frank Miles and the Associated Press contributed to this report