Posted by shark-92107 on February 13, 2001 at 11:39:59:
In Reply to: Mia Tegner's DDRC Final Report posted by Bert on February 13, 2001 at 09:03:39:
Here's the actual DDRC report. I've made a couple of stylistic changes: (1) the original has some tables and check-the-boxes, which I've converted to text; (2) I've deleted addresses and personal information. Otherwise, it's quoted verbatim.
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COUNTY OF SAN DIEGO
OFFICE OF THE MEDICAL EXAMINER
DIVING DEATH REPORT (SCUBA DIVING)
NAME: Tegner, Mia
DATE: 01/07/01
TIME: 2:10 pm
WATER DEPTH: 85'
VISIBILITY: 10-15 ft
TEMPERATURE: Top - 62 degrees, Bottom - 54 degrees
AMOUNT OF SURGE: Lt.
HEIGHT OF WAVES: 1-2 ft.
TYPE OF BOTTOM: Sand
WEATHER CONDITIONS: Clear
OTHER WATER CONDITIONS (KELP, ETC.): Wreck
TIME OF ENTERING WATER: 1:45 pm
LAST SEEN ALIVE: 2:00 pm
TIME SEARCH BEGAN: 2:25 pm
TIME OF RECOVERY: 2:45 pm
WHAT WAS VICTIM'S CONDITION AT TIME OF DISCOVERY: Ocean floor
POSITION OF BODY WHEN FOUND: Supine
EVIDENCE OF INJURY: None
EVIDENCE OF PANIC: Regulator out of mouth
EVIDENCE OF KELP, FISH LINES, ETC.: None
NUMBER OF DIVES ON DATE OF ACCIDENT: 2
EQUIPMENT:
FOUND ON BODY:
diving suit, hood, booties, gloves, mask, fins
weight belt - integrated 40.5 lbs.
type-buckle - pin release (unusable)
flotation device - not inflated, good condition
seq view
regulator - Atomic 2I
tank pressure - empty, where filled - unknown
reserve (up/down) - N/A
NOT FOUND ON BODY:
snorkel, knife, ab iron, flashlight, spear gun
watch (unknown)
WATER EXPERIENCE
SWIMMING ABILITY/YEARS/COURSES: Good, 45, Lifeguard Instructor.
SKINDIVING ABILITY/YEARS/COURSES: Good, 40, Openwater I.
SCUBA ABILITY/YEARS/COURSES: Excellent/expert, 2 [sic], 3-5,000 Dives.
CERTIFICATION DATE: 1974
EXPLAIN PREVIOUS DIVING EXPERIENCE (POOL, OCEAN, ETC.): Marine biologist who dived regularly for many years
PREVIOUS DIVING IN THIS SPECIFIC LOCATION (EXPLAIN): Many previous dives. Very experienced.
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RELATE IN YOUR OWN WORDS THE CIRCUMSTANCES OF THE ACCIDENT: (TO BE FILLED IN BY VICTIM'S DIVING PARTNER)
According to the decedent's husband, also her dive partner, the decedent was a marine biologist, and while this was a recreational dive, she was noting marine organisms associated with the wreck off the shore of Mission Beach for her own interest. A party of five divers were using a privately owned 22' boat as their dive platform. The first dive of the day was on a wreck located in 100 feet of water. She made a single dive in this location without incident. After a surface interval of approximately 1 1/2 hours, the decedent began her second dive on another wreck which sat in 85 feet of water. The decedent began the dive with her husband but after about 20 minutes her husband became low on air and surfaced. The decedent continued to dive until she became low on air then began an ascent. Since there are no witnesses to this event, it can not be determined whether or not the decedent made a safety stop. She was seen reaching the surface and made a statement to the effect that her computer was telling her she need additional decompression time and she needed a different tank in order to submerge again. One of the other divers directed her to his tank, regulator and buoyancy compensator vest which was hanging from a line over the side of the boat. The decedent detached the tank system, held it under her arm and descended. After approximately four minutes, the system rapidly floated to the surface with the buoyancy compensator almost full of air. The decent's husband immediately geared up and entered the water. He descended to the bottom and searched for the decedent and could not find her. He surfaced again to see if she made it safely to the surface. When he did not find her, he descended to the bottom again until he ran out of air. He surfaced once again and summoned help.
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AIR MANAGEMENT
The committee believes the accident began when the decedent did not allow enough reserve air in her system to make a stabilized ascent to the surface in which an adequate decompression safety stop could be included. She stated her computer was telling her that she needed additional decompression time and was forced to surface prematurely in order to obtain additional air. The equipment evaluation revealed significant seawater in the tank indicating no air pressure whatsoever.
BUOYANCY CONTROL
The decedent was diving with 40.5 pounds of weight in her buoyancy control system. When the recovery team attempted to bring her system to the surface, they orally inflated the system to it's fullest capacity. The system remained on the ocean floor and had to be physically propelled to the surface.
The decedent was wearing a dry suit which required the insertion of air from her tank into her suit in order to accommodate comfortable diving and neutral buoyancy. otherwise, the pressure at depth would cause the dry suit to constrict around the decedent's body to an uncomfortable level. By introducing air into the dry suit, the pressure would equalize, resulting in both comfort and buoyancy. With her system, the only way to introduce air into the dry suit was through a low pressure hose running from her scuba tank, through a manually controlled valve and into the dry suit.
EMERGENCY ACTIONS
Since there were no eye witnesses to the last moments of the accident, only educated opinions remain. The Committee believes that the equipment evaluations offer the best clues. When the emergency occurred, it would have been appropriate for her to release her weights which would have made her positively buoyant at depths less than 50 feet. The equipment evaluation indicated that the metal rod that must be pulled in order to release the weights was bent to a degree that the weights would have been very difficult to release, particularly in an emergency. The only other way for the decedent to become positively buoyant, then, would be to take off her entire buoyancy control system. In this case this would have involved releasing two buckles, releasing a low pressure hose leading to her dry suit and taking her arms out of the arm holes of the vest. There is a significant possibility that the decedent was experiencing decompression sickness which may have limited her motor response. Alternatively, the autopsy suggests an air embolism occurred, which may have rendered her unconscious. The recovery team did not notice any attempt by the decedent to get out of her buoyancy control system.
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HOW COULD THIS ACCIDENT HAVE BEEN PREVENTED: (TO BE COMPLETED BY MEMBER OF THE CORONER'S SCUBA DEATH COMMITTEE)
The committee believes the accident could have been prevented in several ways. The decedent could have maintained her gear in such a way that dropping the weights could have been accomplished.
Secondly, the buddy system could have been followed which dictates when one member of the team cannot continue the dive, both surface together. Had a buddy been present, the decedent would have had additional air, buoyancy, and rescue services available. It is by no means certain, however, that a buddy would have changed the outcome of this event.
Third, the decedent could have dived with much less weight that would have enable her to make it to the surface even if her weights could not be ditched. Most diving agencies recommend that the buoyancy system be configured in such a way that enough lift could be generated to counteract the weight system and other negative weight associated with the dive such as the tank, the diver's body and other accessories. With the weight she was carrying, it was difficult for her to stay afloat without a substantial amount of air in both her buoyancy vest or the dry suit. Although the buoyancy vest could be orally inflated, it is improbable a diver would exhale their last breath in order to do so. Shortly after the decedent took control of the second tank, evidence leads the committee to believe the decedent was having buoyancy control problems. It appears she used some of her limited air supplying the second tank to inflate the buoyancy vest connected to the second tank. Again, her motor skills may have been impaired by diving decompression sickness or an arterial gas embolism which may have led to her losing her grasp of the second tank which most likely was her only source of air and buoyancy at the time. She was probably then descending rapidly, without air and without a way to surface. Within several minutes, the decedent most likely became unconscious, then expired.
Finally, the decedent apparently could have managed her air and dive profile in a way that would have left adequate reserves for a decompression safety stop and buoyancy.