Pompano Beach Fatality Sunday April 16th

[aue-mike]

Mike,
I believe you are thinking that as the diver descends on CCR, the loop PO2 will normally increase and can even spike high during a rapid descent typical of technical dives. However, my statement is not at all "problematic". I've investigated several accidents and personally observed one where LOC occurred during or shortly after descent. While descent does cause a relative increase in the PPO2, at the same time the diver is burning oxygen out of the loop that is not being replaced if oxygen supply has failed.

Here is a general example, one of many possible: The CCR diver has properly prepped their unit including a pre-rebreathe during the transit to the dive site. During the transit, the oxygen valve is 'rolled off' as it bounces against a tank rack and bench designed for AL-80's. The loop PO2 is stable at the expected set point, say 0.7 ATA from the pre-prebreathe and indicated pressure on the SPG is as expected as well (from the charged HP hose, which is quite long on some units and holds a surprising amount of oxygen).

Once the dive boat reaches the site the diver dons the CCR, runs an abbreviated pre-jump list, then enters the water and makes a very rapid descent. In our area, this is a typical occurrence especially if the diver is "smart bombing" the wreck. While the loop PO2 is initially increasing, and the solenoid initially injects some oxygen (from the hose residual), eventually the loop PO2 will begin to drop and will rapidly drop if the diver pauses their descent for any reason. The first diver jumping on a technical wreck dive in our area often has the task of chaining in a descent/ascent line for others to follow. That diver is exceptionally task loaded with navigating to the wreck and tying in. If the task loaded diver fails to notice their setpoint is not being maintained (the usual concern being a brief hyperoxic spike, not hypoxia), then LOC follows.

Note, this isn't a hypothetical example, it's has happened to me personally exactly as I described and I was lucky enough to notice dropping PO2 before the loop became seriously hypoxic. I've caught two more roll offs over the years, but before gearing up as I now always manually check the valve immediately before gearing up. I've also personally observed several CCR divers actually perform their pre-breathe and then close the valve as a result of an OC habit. Just to be clear, I'm not proposing the circumstance I've just described above as what happened in the case of the accident being discussed. I'm simply describing my findings in more than one case where LOC on CCR happened during or very shortly after rapid descent.

Appreciate the response Mark. Yes, these scenarios can happen as described. And I am aware of incidents where divers have gone hypoxic and perished on the bottom due to O2 valves being turned off. But IMHO this speaks of poor training, experience, and practices.

EDIT:
"While the loop PO2 is initially increasing, and the solenoid initially injects some oxygen (from the hose residual), eventually the loop PO2 will begin to drop and will rapidly drop if the diver pauses their descent for any reason."
I don't think I would agree with your assertion that the PO2 would "rapidly drop if the diver pauses their descent for any reason." During our CCR training, our instructor had us set our PO2 at a safe level (can't remember the specifics, but let's say, e.g., 0.50) and then shut off our O2 to monitor the rate of our PO2 drop while our instructor observed/monitored the situation. During our course, we even kicked against the side of the pool to see how fast one could burn (metabolize) through O2. It was definitely not "rapid" in our experience. But perhaps I am misunderstanding your point.

I know we could easily delve into semantics and "chicken versus egg" discussions, and will concede these scenarios would ultimately be considered hypoxic fatalities, but that is not, nor should not, be the real trigger. It's clearly human error.

 

[doctormike]

I have not taken anything you posted in here as a slight against Joe. And I did not state nor imply hypoxia is not something to be considered. I considered hypoxia, but based on the information I posted (and additional information not for public dissemination) and my lengthy personal experience with Joe, considered it to be unlikely over other scenarios.

Right. But a brief cryptic comment suggesting that considering hypoxia is "fundamentally problematic" with no context works against the process of accident analysis. Especially if that comment is based on information that is not available to other members of the thread. Not everyone here is a rebreather diver.

I'm not trying to be difficult or give you a hard time. I appreciate your expertise (and of course, offer my condolences). I just think that it would have been better to just explain why you felt hypoxia was unlikely in this case based on whatever information you feel comfortable sharing.

Over the past 3+ years, Joe had focused on diver education. Over that time he instructed numerous technical divers, be it for cave diving classes, CCR classes, etc. I know Joe would want to know what happened, and would want to educate other divers on the accident circumstances for their benefit. Which is why I opted to now wade into this to try to provide some useful context and information.
The universe of potential CCR failure modes and diving accident/incident causes is well documented. If one wants to simply consider/conclude the cause of death was due to either: 1) hypoxia; 2) hyperoxia; 3) hypercapnia; 4) medical issue; 5) gear issue; 6) human error; 7) some combination of the above; 8) etc., -- especially before any detailed gear analysis or coroner report (which 99/100 are unhelpful) has been conducted or released -- then we don't need to have this forum as it will always be covered by something within this spectrum. And per your statement: "It's not a legal deposition trying to determine precisely what happened in this particular case to this particular diver." If we are not trying to determine the particulars of the incident, just what is the point of this forum?

Sorry, I disagree. The point of the forum is - in my opinion - NOT to determine what happened in a particular case. With few exceptions, we rarely can do this because of concerns about liablity, the limits of any formal investigation, and other factors (especially in US cases, where there is no formal reporting mechanism). The point of this forum is to use these cases as a springboard for discussion so that people can learn from tragedy and become better divers. Even if the lesson that they learn may not be what actually happened in the case.

The best way to learn about failure modes and how to avoid the next accident is to take quality diver training and surround yourself with solid, like-minded, safety-conscious divers. It's that simple.

Yeah, but this helps too. Sometimes things don't come up in training, and the only way you think about them is through accident analysis.

 

[aue-mike]

Right. But a brief cryptic comment suggesting that considering hypoxia is "fundamentally problematic" with no context works against the process of accident analysis. Especially if that comment is based on information that is not available to other members of the thread. Not everyone here is a rebreather diver.

I can see that. But I made that comment to allow folks to engage their brains to hopefully recognize the concerns about the referenced conclusion/scenario. And the points I raised (depth/pressure effects on PO2 and gas volume) are fundamentals of all diving, not just CCR.
While I again appreciate your input about basing comments on information that is not available to other members of the thread, that does cut both ways. That is, coming to conclusions or offering scenarios without knowing all the particulars of an incident may also work against the process of accident analysis. And therein lies the rub...

 

[doctormike]

I can see that. But I made that comment to allow folks to engage their brains to hopefully recognize the concerns about the referenced conclusion/scenario. And the points I raised (depth/pressure effects on PO2 and gas volume) are fundamentals of all diving, not just CCR.
While I again appreciate your input about basing comments on information that is not available to other members of the thread, that does cut both ways. That is, coming to conclusions or offering scenarios without knowing all the particulars of an incident may also work against the process of accident analysis. And therein lies the rub...

Right, i think that we are pretty much on the same page, and it may be semantics. Accident Analysis really isn't what we are doing here - that implies a formal investigation to figure out exactly what happened in a particular case. Like the FAA process.

I really don't think that's why this forum exists. In fact, in many cases, online fourms work against that process, by giving the weight of expert opinion to scenarios that don't accurately reflect what happened. Sort of like what happened with my dive buddy's loss of her instabuddy last year in Newfoundland.

Obviously, people get different things out these forums. Personally, I find the discussion helpful and interesting, and i have learned a lot, even from "off topic" threads!

So I'm fine with conjecture and hypothetical scenarios, as long as all of the discussants understand the nature of those posts, and don't conclude that the opinion of the loudest voices here represent the truth.

 

[L13]

...
Over the past 3+ years, Joe had focused on diver education. Over that time he instructed numerous technical divers, be it for cave diving classes, CCR classes, etc. I know Joe would want to know what happened, and would want to educate other divers on the accident circumstances for their benefit. Which is why I opted to now wade into this to try to provide some useful context and information.

Given this, why is there:

(and additional information not for public dissemination)

Any accident relevant information should be public. And based on your statement about Joe and what he would want, he would agree.

It is rather hard for anyone to evaluate any statements by anyone hiding the truth about what happened.

It is hard to "educate other divers on the accident circumstances for their benefit", if relevant "accident circumstances" are "not for public dissemination."

 

[aue-mike]

Given this, why is there:


Any accident relevant information should be public. And based on your statement about Joe and what he would want, he would agree.

It is rather hard for anyone to evaluate any statements by anyone hiding the truth about what happened.

It is hard to "educate other divers on the accident circumstances for their benefit", if relevant "accident circumstances" are "not for public dissemination."

Because it is speculative and from personal conversations not supported by follow-up analysis of gear, which won't be available until it's released by the authorities. Furthermore, other bits are opinions based on personal experience with the deceased, and obviously may conflict with actual circumstances so it would obviously be considered anecdotal to those not familiar with the individual.
If you want to focus on that, so be it.

 

[Seaweed Doc]

Because it is speculative and from personal conversations not supported by follow-up analysis of gear, which won't be available until it's released by the authorities. Furthermore, other bits are opinions based on personal experience with the deceased, and obviously may conflict with actual circumstances so it would obviously be considered anecdotal to those not familiar with the individual.
If you want to focus on that, so be it.

Will any relevant details be released by authorities? In other accident scenarios, often we hear nothing. (At least in the US, barring litigation and even there the information will be one-sided.) Occasionally we get "lucky" in that the deceased was diving for a federal agency and there will be a very thorough, balanced public report. The last one of these I read pointed out that a very skilled, very experience diver made at least 3 mistakes. (This was the NOAA diver in Alaska.) That said, from comments made so far I'd lean toward medical event. But we may never know for sure.

I think there's educational value in knowing what MIGHT have gone wrong even if it's not what DID go wrong. We're not a court determining liability or guilt, just a bunch of folks wondering out loud.

 

[kensuf]

So not really information at all?

As of Friday when I left sofla, after attending his funeral the day before, the autopsy report had not been released and the equipment was not released yet. There's really nothing to say at this point beyond what was already posted: something happened that caused him to black out at 160-180' during the descent of the dive, his two dive buddies tried valiantly to save him.

As both Mike and myself said, Joe would have wanted the circumstances to come out, especially if there was something to be learned by his loss that could save another person. That will be honored when there is something to share.

 

[Johnoly]

... There's really nothing to say at this point beyond what was already posted:

I'm not an RB'er. But I also appreciate those friends of Joe's that provide "denials" of details. Like these in the picture { so they can't be quoted & wrongly used }

 

[Altamira]

Many of the older (50-60+) diver deaths I read about are from heart attacks. Clearly scuba diving is causing heart attacks.

If the conditions for a heart attack are imminent, it does not matter whether the individual is diving, playing golf, tennis, hiking, having sex, or any other activity that stresses the heart. I do not think it is appropriate to say diving is causing heart attacks. The individual’s life medical history, genetics, and lifestyle are the cause. Where it happens is incidental.