Caymans Fatality

[DandyDon]

Actually, if I were going to speculate on a cause just based on the meager details provided in the story, I would lean towards cardiac incident. Diver over 45, had incident at surface or while surfacing at end of a shallow, easy dive...but that is just pure speculation. A bad air incident would typically affect more than one diver on the boat and would happen earlier in the dive, not at the end. Hopefully we will eventually get more details or an update from Red Sail about the details of the incident.

Ok, I am not speculating that it was bad air. That thought was mentioned in passing above, probably not seriously, but it's true that you don't know if you don't test yourself. It's not a common problem but only takes once, and I did feel a little silly testing with all of the zeros until I got my first 5ppm - and got excited once headed to a deep dive when we got 17! We turned the boat...

To reply directly tho...
1: Yes, you can draw one bad tank alone from several; and
2: It's most likely to hit you on ascent when partial pressure of O2 decreases but CO is bound to red blood cells.
That's a real problem in that if you think something may be wrong, ascending makes it worse.

It's rare that you need your buddy to share air, but you still want him to be there with two second stages.

 

[Mark Derail]

[Edit: Thanks Dandy Don for the PM's] I'm getting a CO analyser before my trip out to GC.

More info please...PM if you prefer to not detract from subject, but it could be related...
(tester as stated in your signature? easy to use? bought at a dive shop?)

Ok, I am not speculating that it was bad air. That thought was mentioned in passing above, probably not seriously, but it's true that you don't know if you don't test yourself. It's not a common problem but only takes once, and I did feel a little silly testing with all of the zeros until I got my first 5ppm - and got excited once headed to a deep dive when we got 17! We turned the boat...

To reply directly tho...
1: Yes, you can draw one bad tank alone from several; and
2: It's most likely to hit you on ascent when partial pressure of O2 decreases but CO is bound to red blood cells.
That's a real problem in that if you think something may be wrong, ascending makes it worse.

It's rare that you need your buddy to share air, but you still want him to be there with two second stages.

 

[AggieDiver]

I wasn't directly responding to your post Don, sorry if it appeared that way. I was just responding to Mark's speculation about a bad air incident above that. I agree in a shop fill scenario, you could pull one bad tank from many tanks filled over a period of time. However, most of the larger operations like Red Sail will fill large batches of tanks, and it would be rare for one diver to get a tank that was vastly different than all others on the boat. I am not by any means trying to diminish the value of doing your own testing and I applaud your efforts to publicize it here. Until we get more details, it will all remain just speculation, but I told my wife right after we heard about the story, that based on past incidents in GC, most likely, given the age, operator, and details given, it was an American cruise ship passenger who hadn't been diving much that had a heart attack while surfacing. Again...total speculation on my part, but given the history of events on GC, it is far more likely than a bad air incident.

 

[sskasser]

[Edit: Thanks Dandy Don for the PM's] I'm getting a CO2 analyser before my trip out to GC.

More info please...PM if you prefer to not detract from subject, but it could be related...
(tester as stated in your signature? easy to use? bought at a dive shop?)

This a pretty common mistake, but to clarify, you want a CO analyzer, not CO2. CO - carbon monoxide - is what has been known to get into SCUBA cylinders and kill. It's what comes out of your car's tailpipe, compressors, and out of a smoker's mouth. CO2 - carbon dioxide - is what we exhale and I'm not aware of any instances of it getting into a cylinder and killing the user.

 

[Mark Derail]

Thanks for the clarification, I added the '2', makes sense now. Even the website for the product mentioned above says CO and not CO2. Post edited.

Ordering one tonight!

This a pretty common mistake, but to clarify, you want a CO analyzer, not CO2. CO - carbon monoxide - is what has been known to get into SCUBA cylinders and kill. It's what comes out of your car's tailpipe, compressors, and out of a smoker's mouth. CO2 - carbon dioxide - is what we exhale and I'm not aware of any instances of it getting into a cylinder and killing the user.

 

[citycountryguy]

If I can ask a question without hijacking....is there any known instance of CO being an issue in a nitrox tank?

 

[AggieDiver]

I can't think of any that have been discussed here off the top of my head. 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.

 

[Mark Derail]

There is a follow-up to this story in the Cayman Islands thread, where the sister makes a nice statement to the local newspaper.

 

[sskasser]

If I can ask a question without hijacking....is there any known instance of CO being an issue in a nitrox tank?

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

 

[heavierthanlead]

There is a follow-up to this story in the Cayman Islands thread, where the sister makes a nice statement to the local newspaper.

http://www.scubaboard.com/forums/cayman-islands/410519-nice-letter-editor.html