Truth Aquatics had a good reputation locally, and maintained their boats in good condition, according to
state Senator Hannah-Beth Jackson, who represented the Santa Barbara area. The
National Transportation Safety Board (NTSB) launched a go team on September 3 to the accident to investigate. The on-scene portion of the investigation was scheduled to last for ten days, with the objective to determine the cause of the fire and verify the safety measures that had been aboard
Conception. Speaking on September 3, Member Homendy said she was "one hundred percent confident that we will learn the why and the how" behind the accident. Agents with the
Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) immediately responded, but investigatory agents did not arrive until September 7, to investigate the point of ignition and cause of the blaze. On September 9, law enforcement sources told the
Los Angeles Times that a joint federal criminal investigation was underway, led by the Coast Guard, joined by the FBI and ATF, and under the oversight of the
United States Attorney for Los Angeles. The focus of the investigation is on records retrieved from the offices of Truth Aquatics, prompted by a preliminary investigation which indicated potential deficiencies in crew training, passenger safety briefings, and the failure to use a roaming "night watchman". On September 11, the Coast Guard announced it would convene a formal
Marine Board of Investigation (MBI) for the fire and loss of
Conception. The four members of the MBI will determine contributing factors, including whether the actions of certified people or any Coast Guard or government personnel may have contributed to the loss. The Coast Guard named Captain Jason Neubauer as the chair of the MBI. However, the MBI had not been convened by October 2020. Some parts of the boat have been removed and sent to laboratories for further examination.
Salvage Derrick barge Salta Verde () arrived at Santa Cruz Island to assist with the
salvage operation on September 4. Divers examined the wreckage to prepare to raise it, but high winds and heavy seas hampered the recovery plans. The FBI assisted this portion of the investigation due to their experience in evidence preservation. DB
Salta Verde transported the boat to a secure location at
Naval Base Ventura County through the
Port of Hueneme on September 13. The wreck of
Conception was inspected over the next thirteen days by the Coast Guard, Bureau of Alcohol, Tobacco, and Firearms, Federal Bureau of Investigation, and the Santa Barbara Fire Department. National Transportation Safety Board investigators were permitted to examine the wreck on September 24 and 25. One of the surviving crew members theorized the fire may have started in the salon of the ship, where cellphones and cameras had been plugged in to charge overnight. The designer of the vessel speculated the fire may have begun in the bunk area, possibly sparked by a lithium battery. Boats made at the time the
Conception was built were not installed with electrical systems that could handle the number of rechargeable devices carried by current passengers, who often bring cell phones, cameras, and lighting systems for their dives. The sheer number of devices charging at once may have overloaded circuits, or the devices'
lithium-ion batteries may have overloaded. In October 2018, two passengers aboard the sister ship
Vision saw a battery and charger catch on fire in the aft portion of the salon; one unplugged it and dunked it in a bin of rinse water, and the other emptied a fire extinguisher onto the aft bookcase where it had been plugged in. The NTSB planned to take remnants of any devices charging in the boat to their headquarters near Washington, D.C. for further examination.
Areas of concern While there were
smoke detectors on the
Conception, the surviving crew did not believe any alarms sounded before they discovered the fire. The detectors were of the standard type for home use, which, at the time both
Conception and
Vision were built, met existing safety requirements. MSIB 008-19 also advised that firefighting and lifesaving equipment should be checked immediately to ensure it is onboard and operational. in violation of the conditions in the vessel's Certificate of Inspection MSIB 008-19 advised owners, operators, and masters to review the vessel's Certificate of Inspection to ensure that crewmembers are aware of and understand any conditional requirements, including any crewmember obligations during an emergency. In addition, emergency escapes were to be clearly identified, verified functional, and free of obstructions. A lawyer representing Truth Aquatics disputed this assertion, and stated that one crew member had checked on the galley area around 2:30 a.m. on September 2. Officials believed that all the deceased sleeping below decks had died from smoke inhalation before they were burned. The NTSB released findings from its report on the incident on October 20, 2020. The report stated that the deaths may have been prevented if the boat had a roving watchman, as required by regulations. Investigators found several bodies wearing shoes, and believed that some of the victims may have been awake and trying to escape before being overcome by smoke. Member Homendy added "Some people may walk away and say, 'Well, I wish I knew what the ignition source was.' But the key here is that the focus should be on conditions were present that allowed the fire to go undetected and to grow to a point where it prevented the evacuation." A spokesman for the Coast Guard stated the agency had embarked on a concentrated inspection campaign for every small passenger vessel with overnight accommodations shortly after the preliminary results had been determined. Because the required Coast Guard vessel inspection occurs in port, without passengers embarked, there is no way to verify compliance with the night patrol requirement. The NTSB has no regulatory enforcement ability and relies on other agencies to implement the recommendations from its investigations. Sumwalt added "This tragedy did not need to happen. We hope that our actions from today will prevent such disaster in the future." Truth Aquatics was also faulted for "deviating from required safe practices for some time" prior to the accident, despite their reputation for operating, according to a former captain of the sister boat
Vision, "the safest boats on the coast". because the fire likely started in the salon, away from the passenger berths and the galley area, the fire was already well-developed by the time the smoke and heat detectors could alarm. If the smoke detectors were deployed in all passenger spaces, not just their sleeping berths, and were interconnected so that all would alarm when any one detected smoke, that would have increased the chance the fire could have been detected early enough to allow for effective firefighting and evacuation.
ATF investigation Slim Jim polyethylene trash can in 2019. A confidential ATF report authored in January 2021, and reported in September 2023, concluded that the fire began in a plastic trash can below the stairs leading up to the main deck, which blocked the escape route of passengers from the bottom deck. The ATF's investigation used burn tests simulated on a full-scale recreation of the vessel's main deck, and found that the flames would have blocked all escape routes soon after ignition, and any winds blowing would have spread the fire even more quickly. Contrary to the NTSB's investigation, the ATF found that there was no evidence to support that the fire originated from a power strip where passenger's batteries were charging. == Legal action ==