SEATTLE – A sailor who died in an apparent accident on the nuclear missile-carrying submarine USS Nebraska off Hawaii has been identified.

A Navy news release identifies the sailor as 21-year-old Machinist Mate 3rd Class Michael A. Gentile of Fairfield, Maine. He joined the Navy in 2005 and was previously assigned to the Alaska, another one of the Navy’s 560-foot Trident nuclear-powered subs.

Few details have been released on what happened Saturday while the submarine was beneath the surface of the ocean off the island of Oahu. The Navy Times quoted the Naval Safety Center as saying Gentile became “entangled and pinned” in the ship’s rudder.

Navy officers said Gentile was given emergency medical treatment but died in a medical helicopter en route to a hospital.