LOS ANGELES >> The Coast Guard has announced several new safety rules following the deadly blaze that sent dozens of people on a scuba diving boat to a watery grave off the California coast more than two years ago.

The Labor Day 2019 fire that killed 34 people aboard the Conception off Santa Barbara marked the deadliest marine disaster in modern state history and led to criminal charges and calls for tougher regulations for small passenger vessels.

Under interim rules that take effect over the next two years, boat owners will be required, among other things, to install fire detection and suppression systems, provide better escapes and use devices aboard that make sure a night watchman is alert and making frequent rounds.

An investigation into the disaster blamed the Conception’s owners for a lack of oversight and the boat’s captain for failing to post a roving watchman aboard the vessel, which allowed the fire to quickly spread and trap the 33 passengers and one crew member below deck. Captain Jerry Boylan and four crew members, all of whom were sleeping above deck, escaped.

Boylan has pleaded not guilty to 34 counts of seaman’s manslaughter. He is free on bond awaiting trial in U.S. District Court in Los Angeles.

The new rules were expected after Congress mandated in December 2020 that the Coast Guard review its regulations for small passenger vessels. The law, included in the National Defense Authorization Act, also added new requirements regarding fire detection and suppression.

The National Transportation Safety Board recommended in its investigation that the Coast Guard require boat owners to install more comprehensive smoke detector systems, upgrade emergency exists and make mandatory inspection checks on roving watches.

Since 1991, no owner, operator or charterer has been issued a citation or fine for failure to post a roving patrol, prompting the NTSB to fault the Coast Guard for not enforcing that requirement and recommend it develop a program to ensure boats with overnight passengers actually have watchmen.

The rules published late last month in the Federal Register begin taking effect March 28 and could be changed after a public comment period that ends in June.

They do not apply to ferries or fishing boats.

Other requirements include better training of crew, escape drills for passengers and guidance on how to handle flammable items such as rechargeable batteries.

While investigators said they couldn’t determine what caused the fire because the boat burned and sank, they say the blaze started toward the back of the main deck salon — where divers had plugged in phones, flashlights and other items with combustible lithium ion batteries.

After the fire, the Coast Guard issued a bulletin recommending a limit on the unsupervised onboard use of lithium ion batteries and extensive use of power strips and extension cords.