Abstract: On September 28, 1994, Employee #1 and a coworker, both Los Angeles County Lifeguards, conducted a reef recognition dive in an area off Catalina Island, CA. The lifeguards were diving with county scuba equipment, including buoyancy vests, submersible depth gauges, timers, compasses, and single hose, two-demand regulators. They were each wearing fins, full length wet suits, gloves, and scuba masks. They reached a depth of 90 ft and had been there for approximately 15 minutes when Employee #1 began to have trouble drawing air from his regulator. He checked his depth gauge and attempted to activate the J valve, or air reserve mechanism, located on the manifold of his scuba tank. He also notified his dive partner that he was returning to the surface. Partway into his ascent Employee #1 could no longer breathe through his regulator at all, so he returned to his partner and attempted to buddy breathe from his partner's top regulator. As he was doing this, Employee #1 swallowed some water and was forced to ditch his weight belt and return to the surface. Upon arriving at the surface, Employee #1 lost consciousness and stopped breathing. His partner performed rescue breathing until medical assistance arrived. Employee #1 regained consciousness and was then transported via Mercy Air Ambulance to Torrance Memorial Hospital.