Caymans Fatality

[Texas Torpedo]

Yes, I'm down one friend because of that specific issue. It's been discussed here.

I was about to mention the same.. Sadly, I never got the chance to meet him..
Link: http://www.scubaboard.com/forums/ac...-tourist-dies-while-diving-cozumel-caves.html

However, there is no reason why nitrox tanks would be any different than regular air tanks, because all most operations do is blend O2 with regular air to make nitrox. Since the CO contamination comes in from the air compressor, there is no reason it couldn't wind up in a nitrox tank. But it would be slightly diluted by the O2 added to the air.

Actually, that is not always the case, IMO. There are a number of variables that could affect this.. If continuous blending a small Nitrox bank, or simply topping off partial pressure Nitrox fills with a compressor while a diesel truck is parked near the intakes, you could get isolated contamination strictly for EAN tank fill(s), or vice versa. Fortunately, it is rare, but I believe something like this got Brendan, and almost Lamar English: The Deco Stop

The above didn't happen in the Caymans.... But, it could..


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[Ken Kurtis]

Greatest worry is always bad air in the cylinder.

Not to make light of the incident or the seriousness of CO poisoning, but . . .

Your greatest worry should be bad decisions made by a diver (any diver) that can set in motion a chain of events that directly leads to death.

Based on a survey I did of DAN fatality stats from 2003-2006:
> 6% bad luck (wrong place, wrong time - like getting hit by a boat when you surface)
> 25% medical (coroner's report specifically said heart attack or stroke or something like that - some speculate this number could be as high as 40%)
> 69% bad diving (dumb decisions by the diver which include running out of air, diving beyond training, etc.)

In a DAN survey on 947 fatalities over a 10-year period where 350 had an identifiable trigger:
> 41% of the fatalties had out-fo-air as the trigger that started the dive going downhill

Unconsciousness upon surfacing is a classic symnpton of - but not exclusivley limited to - air embolism. [PURE SPECULATION FOLLOWS AND IS ITALICIZED] Just based on the meager info, she could have had some problem on ascent and inadvertently held her breath, or could have run out of air on ascent and tried to free ascend unsuccessfully.

I'd be curious to know what the medical report/autopsy says.

- Ken

 

[AggieDiver]

Actually, that is not always the case, IMO. There are a number of variables that could affect this.. If continuous blending a small Nitrox bank, or simply topping off partial pressure Nitrox fills with a compressor while a diesel truck is parked near the intakes, you could get isolated contamination strictly for EAN tank fill(s), or vice versa. Fortunately, it is rare, but I believe something like this got Brendan, and almost Lamar English: The Deco Stop.

Just to clarify, I wasn't trying to say all air tanks from an operation would have the same CO as their nitrox tanks. I was saying that the same processes that are capable of introducing CO to air tanks would be capable introducing CO to nitrox tanks, so there was no reason from a fill process perspective that nitrox tanks wouldn't be at risk of having CO in them.

 

[Texas Torpedo]

Not to make light of the incident or the seriousness of CO poisoning, but . . .

Your greatest worry should be bad decisions made by a diver (any diver) that can set in motion a chain of events that directly leads to death.

Ken, I agree and it is obvious this is a far greater factor than the known CO related deaths... For me personally, I simply prefer to eliminate as many unknowns as possible. Can't ever hurt.

Based on a survey I did of DAN fatality stats from 2003-2006:
> 6% bad luck (wrong place, wrong time - like getting hit by a boat when you surface)
> 25% medical (coroner's report specifically said heart attack or stroke or something like that - some speculate this number could be as high as 40%)
> 69% bad diving (dumb decisions by the diver which include running out of air, diving beyond training, etc.)

In a DAN survey on 947 fatalities over a 10-year period where 350 had an identifiable trigger:
> 41% of the fatalties had out-fo-air as the trigger that started the dive going downhill

Good stats but hasn't DAN also stated that they do not know how many medically related fatalities may have potentially been triggered by "bad air"?

Unconsciousness upon surfacing is a classic symnpton of - but not exclusivley limited to - air embolism. [PURE SPECULATION FOLLOWS AND IS ITALICIZED] Just based on the meager info, she could have had some problem on ascent and inadvertently held her breath, or could have run out of air on ascent and tried to free ascend unsuccessfully.

I'd be curious to know what the medical report/autopsy says.

- Ken

Absolutely... And me too.. Hopefully it won't just say "drowning", if we see it at all..

David

 

[Ken Kurtis]

Good stats but hasn't DAN also stated that they do not know how many medically related fatalities may have potentially been triggered by "bad air"?

Well (and I'm not suggesting you're trying to skew things), phrased that way, it makes it sound like there are many, many cases of bad air that go unreported. I can't speak for DAN but I think what they've said is that we (the industry) don't really know if it's a lot or a little because many times the air doesn't get tested. It could be a lot, it could be none. My personal belief, based on the cases I've been involved with and others where I've got access to the work other have done, is that the cases of bad air causing the fatality are exceedingly remote.

Now that doesn't mean to say there's no value in carrying a CO tester and analzying each tank you're getting. It may only be a one-in-a-million chance but when you catch that one, you'll be glad that you had the analyzer.

By the same token, everyone knows you analyze your nitrox tanks for O2 content, but does anyone analyze their air tanks for O2? If there's an analyzer handy, it can't hurt to make sure you're getting 21%. We had a case here in LA where the air tested out at 14% O2. Although we don't think that factored directly into the cause of the fatality, it was an interesting find.

- Ken

 

[Texas Torpedo]

Hi Ken,
I apologize if I may have sounded like I was trying to skew anything... That was not my intent.. I was trying to point out that there seems to be a fair number of unknowns, especially if CO poisoning is not suspected and tests therefore are not done on people who have died of "heart attacks", etc.. It makes me wonder how many people who end up feeling sick post-dive (especially groups) may be suffering from low dosages of CO. No proof, of course.. Just speculation.. Until more people are testing their own gas and reporting, we won't know..

As for your question about testing air for 02 content. I do that every time as well, and I think it would be ideal if everyone did...
I will say that I've tested more "air" tanks with elevated levels of 02 than I've gotten C0 hits, but I'm not sure about the 1 in and million chance with C0. I know Dandy Don has been on a boat with elevated levels which they turned the dive, and I know another who tested elevated CO in a 100% 02 fill. Then you have Benden's confirmed fatality from CO poisoning in Coz last year, and Lamar English & Mark Meadows long-term debilitating injuries from bad gas which could have easily killed them. Of course, there's that incident with the Russian diver and those who were lucky enough only to be sick.

I'm curious about the 14% fill fatality. Was it tested for other gases such as He? What type of dive was it?
Thanks,
David

 

[Ken Kurtis]

It makes me wonder how many people who end up feeling sick post-dive (especially groups) may be suffering from low dosages of CO.

Possibly more of those than fatalities. A buddy of mine survived such a situation and he knew for 30 minutes of the dive than there was something wrong, but just kept on going. One problem when discussing the "safety" of diving is that we, as an industry, don't track the close calls. We don't know how many people just "felt sick". We don't know how many people panicked on the surface but the DM jumped in and saved them. We don't know how many people ran out of air and successfully made it to the surface. Were we able to get a better handle on these non-fatal incidents, we'd have a much more accurate picture about the various maladies that can befall us and their individual liklihood.

. . . but I'm not sure about the 1-in-a-million chance with C0.

Poetic/literary license. A phrase people easily understand. Didn't mean to imply that that's really the number I think it is.

I'm curious about the 14% fill fatality. Was it tested for other gases such as He? What type of dive was it?

Deep dive, solo diver, to 200+. Had multiple dives on the computer when downloaded to that depth so it wasn't an unusual dive. Passed out on ascent at 100 feet and was found there much later after they didn't respond to the roll call on the boat. Had AQMD run a full test on the tank and it was 14% O2 and 86% N2. They felt it was a blended tank (not from a compressor) as there were almost no traces of CO or CO2 as you might get from an air compressor sucking in atmospheric air. No evidence of foul play and the PPO2 at the depth s/he passed out (4atm) should have been enough to keep him/her conscious, even with 14% O2 overall. Based on some things going on in the personal life, I have speculation that it may have been suicide but I have absolutely no hard evidence to back that up other than the fact that s/he died and there's nothing else we found that pointed to a cause of death.

- Ken

 

[Thalassamania]

With a 14% report the first thing I'd do is ask for a retest. If that came back the same I'd want to know what kind of tank (if I recall 14% is about where a steel with salt water in in would stabilize after a year or so of warm storage). That sort of mix is know as NARTOX and I've never heard of it being used outside of rather unusual deep commercial and scientific diving.