Diver

A woman, right, is comforted at the scene where a 51-year-old diver from Orange County was reported missing and later found by rescue personal at Shaw's Cove. The diver was part of a group and after a head count it was determined he was missing. The man was rushed to Hoag Hospital on a lifeguard boat. (Don Leach / Coastline Pilot / April 12, 2013)

The missing diver rescued off Shaw's Cove in Laguna Beach became separated from his classmates during a class dive, Laguna Beach lifeguard officials said Monday.

Mark Gibbs, a 51-year-old Tustin resident, died at 1:28 p.m. Friday at Hoag Hospital in Newport Beach, according to the Orange County coroner's office.

Gibbs separated from his classmates at 25 feet below the ocean's surface and was found with an empty scuba tank, Laguna Beach Marine Safety Lt. Kai Bond said.

Newport Beach lifeguards and rescuers from the Orange County Harbor Patrol, Orange County Sheriff's Department and U.S. Coast Guard searched the area and pulled Gibbs from the water at 12:40 p.m., more than an hour after the first 911 calls came in reporting him missing, a Laguna Beach police news release said.

Gibbs was found unresponsive, according to the coroner. Lifeguards placed him onto a boat and started CPR, Bond said.

Gibbs was in cardiac arrest en route to the hospital, Marine Safety Chief Kevin Snow said.

Divers in the class used 15- to 20-pound weights to keep themselves from resurfacing during a dive, said Bond, who added that it appears Gibbs began the dive with a full tank of oxygen.

"He was a certified diver, but I don't know how many dives he had done," Bond said. He added that 25 feet below the surface, the depth at which Gibbs was found, "is typical at Shaw's Cove. It is a popular place."

Gibbs was part of a group from Dive & Photo in Irvine. A representative from the dive shop declined to comment.

Laguna Beach lifeguards and Fire and Police departments responded to the 1000 block of Cliff Drive after 911 callers said they heard people screaming for help in the ocean off Shaw's Cove at 11:21 a.m., according to police.

Classmates conducted a head count and noticed Gibbs was missing.

bryce.alderton@latimes.com

Twitter: @AldertonBryce