Pompano Beach Fatality Sunday April 16th

[gamon]

Why...8 out of 10 diver deaths I read about the person was on CCR. It's a striking correlation, no?

Your logic makes perfect sense. Rebreathers are inherently more complex and risky, there's a disproportionate amount of accidents and fatalities with rebreathers, therefore if there is a fatality and the diver was using a rebreather it's common sense to make the connection between the two.

Just like if we discovered a recreational diver was old, or morbidly obese and a heavy smoker, we could reasonably postulate that the fatality was likely to be related to a medical incident.

 

[doctormike]

He was using a rebreather...'nuff said.

No informed and educated scuba diver - and certainly no rebreather diver - would state that CCR does not have risks far beyond those associated with open circuit. While there are a few circumstances where a rebreather is a safety advantage, I would admit that looking at the overall picture, no one dives CCR because it’s safer. And just like in cave diving, people who do this type of diving and the organizations who train people to do it have adopted far more stringent standards than seen in the “check it out, it’s fun!” world of resort discover diving, But even with these guardrails, accidents can and do happen to even the most capable and experienced divers (as seems to have been the case here).

Furthermore, it’s difficult to use statistics to compare relative risks, since the average rebreather dive is “bigger” than the average OC dive in 2023. Since rebreather divers are doing dives that are inherently more dangerous no matter what gear is used, so it’s not scientifically sound to just compare per dive fatality rates. And there are some dives that are no longer commonly done on open circuit at all, as CCR has opened up new horizons of diving. Orbital flights attempted by rocket have resulted in more casualties than orbital flights attempted by trebuchet launch, but that doesn’t mean that the trebuchet is safer.

But my response to your post wasn’t meant to argue the case that rebreathers are safer than open circuit. The point of this forum is to learn from accidents and make us all better divers by exploring known aspects of the accident as well as appropriate hypotheticals. I don't feel that your post does that.

Now there are some forms of diving that people may feel are SO unsafe that they should never be undertaken by anyone. I personally feel that way about depth records, and I have said so in these threads on many occasions. If you feel the same way about CCR, I guess it’s your right to make that claim. That CCR is SO inherently dangerous that it should never be used by anyone, and the root cause of any CCR accident is the CCR. That there is no reason to look into the specific details of the dive, since anyone choosing CCR is doomed from the beginning, and the details are irrelevant.

So if you are making that case, I guess it’s your right. Certainly not a TOS violation.

That's the long form version of “can you not”.

 

[gamon]

If you feel the same way about CCR, I guess it’s your right to make that claim. That CCR is SO inherently dangerous that it should never be used by anyone, and the root cause of any CCR accident is the CCR.

No one on this thread has posted this, including the poster you quoted.

A murder in the mansion certainly casts suspicion on the butler but it doesn't mean the housekeeper is the innocent one.

 

[doctormike]

No one on this thread has posted this, including the poster you quoted.

You are correct. In retrospect, my phrase "That CCR is SO inherently dangerous that it should never be used by anyone" was putting words into the OPs mouth, and I can't assume that. Point well taken.

I stand by the rest of the post, though.

 

[Joneill]

Your logic makes perfect sense. Rebreathers are inherently more complex and risky, there's a disproportionate amount of accidents and fatalities with rebreathers, therefore if there is a fatality and the diver was using a rebreather it's common sense to make the connection between the two.

Actually, common sense would dictate that one should not speculate about “connections” when there is not any meaningful information that supports a connection. It’s senseless and also disrespectful to the deceased diver to do so at this point.

 

[aue-mike]

If the earlier mention that he experienced an LOC during or shortly after descent is accurate then that is consistent with hypoxia due the loop PO2 not being maintained.

Mark-
You are a rebreather diver. Please think about your statement above and why your scenario is fundamentally problematic.
Mike

 

[Kay Dee]

Mark-
You are a rebreather diver. Please think about your statement above and why your scenario is fundamentally problematic.
Mike

I wondered when someone would point this out.

RIP Joe.

 

[doctormike]

Mark-
You are a rebreather diver. Please think about your statement above and why your scenario is fundamentally problematic.
Mike

You mean because PPO2 rises with descent? True, but if there is a problem with O2 (feed or supply), eventually you'll metabolize the O2 in the loop down to hypoxic levels, right? Especially with a lean dil.

I'm assuming that this diver would have picked that up, but at this point with very little known, no reason to rule that out. Especially from the point of view of discussing hypotheticals...

 

[aue-mike]

You mean because PPO2 rises with descent? True, but if there is a problem with O2 (feed or supply), eventually you'll metabolize the O2 in the loop down to hypoxic levels, right? Especially with a lean dil.

I'm assuming that this diver would have picked that up, but at this point with very little known, no reason to rule that out. Especially from the point of view of discussing hypotheticals...

Yes, your PO2 rises on descent...and because pressure on descent is increasing, gas volume in your loop decreases, necessitating the addition of diluent to compensate. Therefore, even with a lean dil, the possibility of going hypoxic on descent is unlikely because you are constantly adding gas with more O2 even if it's a "lean dil" and even with O2 supply off (which is unlikely given additional info below).
I will add that I know the individual in question, having dived with him regularly for 20 years, 15 years of which was on CCR. And it was standard practice for us to only add O2 while on the surface preparing to dive. This was a standard practice as it was used as a backup check that our O2 was on while pre-breathing and checking cell integrity, etc. Therefore, the loop PO2 on the surface upon splashing in would typically have been around 0.60-0.80. Using 10/50 trimix as diluent would also be typical. While considered a "lean dil", I am sure folks can work out the math to determine the shallow depth straight 10/50 would support life for an extended period of time.
I will also add that the incident occurred in the water column, at around 160 fsw and before reaching the wreck, and at around 2 minutes into the dive.
While not ruling out hypoxia, I wouldn't be looking at it as a primary, secondary, or even tertiary scenario given the above.

 

[Vicko]

Plenty of people took a breath of hypoxic dill and died before their body hit the bottom, cutting the o2 is not the only way of passing out.