The fire that killed 34 people on the California diving liveaboard Conception in 2019 originated in a large plastics rubbish bin, according to an as-yet unpublished official report that has been seen by the LA Times.
The conclusion is based on exhaustive laboratory simulations of the fire, which broke out in the early hours of 2 September while the three-deck, timber-hulled liveaboard was anchored off Santa Cruz Island on the last night of a long-weekend trip, as previously reported on Divernet.
Captain Jerry Boylan and four of his crew were said to have been asleep in the wheelhouse, despite the legal requirement for a night watch, but managed to get clear on a dinghy and raise the alarm.
The new report was produced by federal investigators for the Bureau of Alcohol, Tobacco, Firearms & Explosives (ATF). They built a full-scale reproduction of Conception’s middle deck and carried out a series of burn tests that led them to the conclusion, although the source of ignition remains unproven.
No evidence was found to support suggestions arising from initial investigations by another federal agency, the National Transportation Safety Board (NTSB), that the fire could have started in the charging area for lithium-ion camera, phone and computer batteries above the bunk-room. The vessel’s electrical system and improperly discarded smoking materials had also been listed among likely causes.
The 105-litre polyethylene bin, called a Rubbermaid Slim Jim, was located beneath open steps leading up to the main deck. This and other smaller bins around the vessel were described as “highly combustible” and were not allowed to be used in sleeping areas.
Crew-member Mickey Kohls had told investigators that he emptied four smaller bins into the Slim Jim at about 2.35am, and had been woken some 37 minutes later by popping or crackling sounds and saw fire at the foot of the stairway.
This would have been the escape route for the 33 passengers and female crew member who had been sleeping in the bunk-room on the bottom deck. In the event they were trapped as the flames spread, and were all later determined to have died of smoke inhalation.
Each ATF simulation resulted in a wall of flames blocking escape routes within minutes of ignition and even more quickly with an added breeze, according to the report. The bin would have collapsed in just over two minutes, with the saloon above the bunk-room full of smoke after 12 minutes and the rear of the saloon ablaze after 14.
The ATF report suggests discarded smoking materials as the possible ignition source. Boylan smoked cigarettes but claims he threw the butts overboard, while two of the crew who had tested positive for cannabis denied smoking on the vessel.
After what the LA Times describes as repeated delays, Boylan is due to appear in federal court in October on manslaughter charges, which he denies. A Coast Guard investigation into the fire has been delayed pending the criminal case.
The ATF refused to comment on the LA Times disclosures while court proceedings were ongoing. Apart from the criminal case against Boylan, multiple civil suits have been brought by families of the dead against Glen & Dana Fritzler, owners of Conception operator Truth Aquatics, as well as the US Coast Guard.
The service is accused of allowing Truth Aquatics to continue operating for years despite sub-standard safety precautions aboard its vessels. This June, the Coast Guard issued a “critical safety alert” urging commercial boat operators to avoid using combustible rubbish bins like the Rubbermaid Slim Jim.
Also on Divernet: Conception divers’ families sue Coast Guard, Chilling phone footage captured doomed divers, Safety board blames operator for Conception fire, Conception had exit-route exemption, Conception owners move to limit liability, Liveaboard fire leaves 34 dead