The state Department of Labor and the Coast Guard are investigating the death of a diver and off-duty Honolulu firefighter who drowned while working at a moi fish farm off Ewa Beach.

Jeffrey Barbieto, 41, was taking care of underwater fish cages about two miles offshore for Hukilau Foods when he was reported unresponsive at about 2:30 p.m. Tuesday.

The Navy and Coast Guard responded, but Barbieto died that day at Pali Momi Medical Center.

The Honolulu Medical Examiner’s Office determined he drowned.

Coast Guard Cmdr. Jason Neubauer said investigators have recovered Barbieto’s scuba gear as evidence and are interviewing people to determine the main contributing factors to his death.

The Hawaii Occupational Safety and Health Division is leading the joint investigation, Neubauer said.

Both the Coast Guard and the state Department of Labor said the investigation is the first for Hukilau Foods.

Hukilau raises moi in four diamond-shaped cages spread over about 28 acres of the ocean.

The cages — about 50 feet tall and 80 feet wide — are about 30 feet below the surface.

The company’s divers clean, maintain and patch the cages as well as feed the fish, said company President Ryan Murashige.

He said the company is working closely with the Coast Guard to determine what happened, but couldn’t comment on the incident because of the investigation.

Barbieto was a senior diver for Hukilau and one of two safety workers who created safety measures for the company, he said.

"Jeff’s voice was very important" because of his experience with rescues, Murashige said. "He was very dedicated. He was a great guy."

He said the company has 10 employees.

"The entire Hukilau Foods ohana is deeply saddened by this tragedy," he said.

Barbieto worked part time at Hukilau and full time as a rescue specialist with the Fire Department.

A 21-year veteran, Barbieto had been assigned to Rescue 2 company for the past 10 years and helped create the department’s Rescue Watercraft Program and Surface Water Rescue-Surf Certification Program.

"Jeff was also well-known and respected in the community as a superior waterman," said Fire Chief Kenneth Silva in a statement. "He participated in hundreds of ocean and mountain rescues and made a difference in many people’s lives."

In addition to the two jobs, Barbieto had his own rescue company, Ku‘au Rescue, training rescue professionals in surface-water rescue techniques.

"One of the best, fearless," said friend Bryan Amona, who ran Ku‘au Rescue with Barbieto. "He was a lifeguard’s lifeguard, a waterman’s waterman."

He said Barbieto was a mentor who "wanted to share his knowledge," adding, "He was all about the water."

Amona said Barbieto loved adventure and working as a rescue specialist.

In 2000, Barbieto received a commendation from the Fire Department for jumping from a helicopter into the ocean to save two swimmers in rough surf. In 2009 the department again recognized him for rescuing two swimmers caught in strong currents while he was off duty.

Barbieto is survived by his wife, two teenage sons, one of whom is graduating from Saint Louis School on Saturday, and other family members.

"He was all about his kids, all about his family," Amona said. "No matter what, he took care of his kids."