Jerry Boylan was in charge of the 75ft dive boat Conception that caught fire off the coast of Santa Barbara in 2019.
Now he has been indicted by a federal grand jury on 34 counts of seaman’s manslaughter for his part in one of the worst ever US maritime disasters.
“I am glad they finally indicted the captain,” James Adamic told the Los Angeles Times.
Mr Adamic lost his sister, Diana Adamic, brother-in-law, Steven Salika, and niece, Tia Salika-Adamic, in the fire.
“It has to be done to hold someone accountable,” Adamic said.
“But I hope it is a first step, as the owner needs to also be held accountable.”
The family of Charles McIlvain, who died aboard the Conception, have called on Congress to pass a bill requiring stricter standards for fire alarm systems and multiple escape routes.
“We not only want to see those responsible held fully accountable but also ensure this type of disaster never happens again,” said Mr McIlvain’s wife, Jasmine Lord-McIlvain.
The indictment states that the 67-year-old captain “was responsible for the safety and security of the vessel, its crew, and its passengers,” according to the US attorney’s office in Los Angeles.
Boylan, of Santa Barbara, is expected to surrender to authorities at a later date and faces a maximum prison sentence of 10 years for each count.
An investigation into the incident found that the captain did not post a roving nightwatchman on the boat, as is required by maritime authorities.
The fire is thought to have been caused by phones charging and the victims found themselves trapped by the fire in a bunk room with no way out.
Earlier this year the National Transportation Safety Board blamed the boat’s owner, Truth Aquatics, for failing to follow a variety of safety practices.
Company owner Glen Fritzler has faced a string of lawsuits from the families of victims but these are the first criminal charges in the case.
“We and our clients are and will be forever saddened by this tragedy,” Mr Fritzler’s lawyers said in a statement.
Prosecutors say that violations onboard the ship included failure to have a roving patrol, failure to conduct sufficient fire drills and failure to conduct sufficient crew training.
“Our hope is that this indictment leads to the prevention of boating accidents and the senseless destruction of lives through proper precautions and training,” said Kristi K Johnson of the Los Angeles FBI office.