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Accident on Southern Cal Oil Rigs Dive

Discussion in 'Accidents and Incidents' started by Hatul, Nov 11, 2017.

  1. bullfroger

    bullfroger Angel Fish

    # of Dives: 200 - 499
    Location: pa
    43
    24
    8
    hey I'm not speculating just I want to know the facts and wherethey come from?
     
  2. HalcyonDaze

    HalcyonDaze Manta Ray

    # of Dives: 500 - 999
    Location: Miami
    685
    519
    93
    Let's start with the information we've been given:
    • Based on a photo taken prior to the dive, the deceased was wearing a drysuit, back-inflation BC with weight pockets, and had a pony bottle (unknown if it was a bailout or a deco bottle, but looking at how it's rigged I would think bailout) in addition to his main tank. His main tank had a nitrox label, but we don't know what was in it.
    • Based on what was presented in this thread, this was the third dive of the day - the first being the Olympic II and the second being on the Elly/Ellen complex. I do not recall if it has been confirmed he did both of the previous dives.
    • The deceased was reportedly an experienced diver familiar with rig diving.
    • From an earlier post in this thread, the deceased's buddy dove down to 160-170 ft in an unsuccessful attempt to recover him. According to a post on Power Scuba's Facebook page, his only issue after the ascent was a "professed headache;" he was taken for a chamber ride as a precaution.
    From that we can draw some inferences, which are subject to change as more evidence becomes available:
    • He had two buoyancy aids (drysuit and BC) and easily ditchable weights. He would have had several means to arrest a descent if he was able to. If he was an experienced diver familiar with the rigs, I think it unlikely he would have been grossly overweighted.
    • If this was the third dive of the day and the first (Olympic II) was a max depth of 100 ft, I would think it unlikely he would have planned to go below 100 ft on this dive and very unlikely he would go as deep as 130-140. Assuming he had done the first dive and wasn't planning on reverse-profiling well below that depth, in order to get to a depth where narcosis or oxygen toxicity plays a role something else would have to go wrong first.
    • If we assume his buddy had the same gas mix as he did, the buddy made it down to over 160 ft for a short duration without evident toxicity effects.
    Now, what we don't know, or at least I can't recall being presented in this thread or elsewhere, were the conditions at the time of the dive. However, if they had already done the second dive at Elly/Ellen, it would seem that there were no unusually adverse conditions.
     
  3. Kevrumbo

    Kevrumbo Solo Diver

    # of Dives: 1,000 - 2,499
    Location: South Santa Monica Bay/Los Angeles California, USA
    5,596
    1,280
    113
    The best hypothesis for the moment is the one with the fewest assumptions. Therefore Rule Out Hypercapnia w/ or w/o associated Ox-Tox Seizure in Scuba Diving as precipitating cause. . . Primary Cause of Death: Drowning.
    Some References:
     
    Last edited: Nov 19, 2017
  4. MaxBottomtime

    MaxBottomtime Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Torrance, CA
    7,616
    5,774
    113
    One report was that the buddy who went after him saw him unconscious with his reg spit out. It wouldn't matter what depth he was at at that time.
     
  5. boulderjohn

    boulderjohn Technical Instructor Staff Member

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    24,786
    15,712
    113
    I made the previous post from a purely generic point of view, covering all cases I have read about around the world. Since then I have been contacted by someone in an official capacity who told me how things are specifically in Los Angeles County.

    Autopsies are performed in all dive fatalities. The incident is fully investigated, and a report is made. That report is public information. It is not, however, published. All you have to do to get the official report is ask the sheriff's department for it.
     
  6. yle

    yle Instructor, Scuba

    # of Dives: 500 - 999
    Location: Southern California
    531
    348
    63
    That's quite an assumption. It will be interesting to find out what mix was in the victim's cylinder. If it was nitrox, filled on the boat, they do partial pressure fills (if I recall correctly.) Hopefully it was properly analyzed.

    If the buddy was someone the victim was paired with on the day of the trip, there's no reason to assume the buddy was using the same mix. It's possible the victim was using nitrox and the buddy was on air.
     
  7. Kevrumbo

    Kevrumbo Solo Diver

    # of Dives: 1,000 - 2,499
    Location: South Santa Monica Bay/Los Angeles California, USA
    5,596
    1,280
    113
    "Signs and symptoms that need to be observed are hyperventilation, shortness of breath and tachycardia (rapid heart beat), headache and excessive sweating, mental impairment and finally, unconsciousness."
    CO2 Retention

    ". . .Rising blood CO2 (‘hypercapnia’) is a problem in diving for several reasons. First it can cause unpleasant symptoms such as headache, anxiety and shortness of breath. These can precipitate panic. If the levels get high enough CO2 can cause incapacitation and unconsciousness. . ."
    Advanced Knowledge Series: Basic Carbon Dioxide Physiology
     
  8. HalcyonDaze

    HalcyonDaze Manta Ray

    # of Dives: 500 - 999
    Location: Miami
    685
    519
    93
    It seems the assumption is being made that this was an instabuddy with him and not someone he dove with regularly. Do we know that? I'm not familiar with how Power Scuba organizes its trips. By the third dive a diver on air would have had to stay relatively shallow to remain within NDL. That would make it even less likely that oxygen toxicity was the cause.

    And the buddy had just experienced an emergency, legged it down after the deceased to 167 ft, and then come up rapidly, so one would expect him to have been breathing very heavily. We cannot say the same for the deceased prior to the accident.
     
  9. Kevrumbo

    Kevrumbo Solo Diver

    # of Dives: 1,000 - 2,499
    Location: South Santa Monica Bay/Los Angeles California, USA
    5,596
    1,280
    113
    Yes, but again take into consideration for this buddy-pair -and all divers even at the surface experiencing exertion breathing to begin with. . .

    Look again at this simple graphic demonstration of immersion work-of-breathing, exercise, and ambient pressure differential just by trying to talk and tread water at the surface at the same time:

    Now this is somewhat representative and similar to a degree -of the higher stress of the live boat-drop, hard exercising surface swim through swell & current into & under the oil rig platform's boundary, and then the initial descent to depth . . . All SoCal Divers who regularly dive the Rigs experience this, with some days being relatively benign, and at other times a physical challenge just kicking out to the structure and recovering on surface for a few minutes before starting the descent.

    A fair assumption and valid point of speculation is that the deceased could have been having exertion problems (Tachypnea) right at the start, as early as the surface swim, and still elected to proceed with the dive. Now under immersion and hyperbaric conditions, the vicious cycle of CO2 toxicity commences and the victim goes into Hypercapnia at depth.
     
    Last edited: Nov 20, 2017
  10. yle

    yle Instructor, Scuba

    # of Dives: 500 - 999
    Location: Southern California
    531
    348
    63
    I didn't assume anything. I was simply pointing out that your assumption was a bit of a stretch in logic. There's no good reason to assume that the victim and buddy had the same gas in their cylinders.

    You stated "If we assume..." and then went on to imply that since the buddy made it to 160 feet without ill effects, we could conclude something about the gas in the victim's cylinder. Regardless of the relationship between victim and buddy, there's no reason to assume they were using the same gas.

    I will agree with you that conservative planning of a third dive on air should require a shallower depth than might have been reached on the first two dives. So if the dive was planned conservatively and if the dive plan was followed, then we could expect oxygen toxicity risk would have been mitigated.

    The only thing we can conclude with certainty is there are a lot of "ifs."
     

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