He is very much associated with Undercurrent.
Unknown Tourist dead, Dive Master ill - Ambergris Caye, Belize
- Thread starter DandyDon
- Start date
This Thread Prefix is for incidents when the cause is not known.
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For those who are subscribed to undercurrent, was there any new information in their article or more of the same?
Belize Diving Death; Always Test Your Air
While divers know to analyze their nitrox before a dive, they may not think it important to analyze
compressed air. But, with operations producing all sorts of mixes these days, one should analyze
both nitrox and air.
This was borne out by an incident in Belize on June 11 when two nitrox divers became ill during a
benign 60-foot dive. Initial reports tell that the Belizean divemaster leading the group was
recovered by a woman in the group breathing straight air, who successfully administered CPR at the
surface. The other diver, a US citizen, appears to have made an uncontrolled ascent leading to
embolism and death after he became unwell at depth. He sank back down from the surface to the
seabed.
The content of their tanks are suspected of either being contaminated with CO or having a
too-rich oxygen mix, leading to toxicity at depth. The dive operator was Ambergris Divers, which
has not responded to our request for more information.
It's unlikely CO poisoning was the culprit since that would have been due to a faulty compressor
installation and affected more tanks. All the other divers appeared to have no problems.
It's more likely that the nitrox mix is suspect. This can happen especially if the nitrox is made
by partial pressure blending (when neat 02 is added to a tank and then
topped up with air) rather than de-nitrogenizing air through a membrane system. CO analyzers tend
to be expensive and complex to use- but anyone can buy a personal nitrox analyzer They can cost
around a couple of hundred dollars (Vandgraph, Divesoft, etc). Always check to know what you're
breathing- even if you think you're getting straight air.
compressed air. But, with operations producing all sorts of mixes these days, one should analyze
both nitrox and air.
This was borne out by an incident in Belize on June 11 when two nitrox divers became ill during a
benign 60-foot dive. Initial reports tell that the Belizean divemaster leading the group was
recovered by a woman in the group breathing straight air, who successfully administered CPR at the
surface. The other diver, a US citizen, appears to have made an uncontrolled ascent leading to
embolism and death after he became unwell at depth. He sank back down from the surface to the
seabed.
The content of their tanks are suspected of either being contaminated with CO or having a
too-rich oxygen mix, leading to toxicity at depth. The dive operator was Ambergris Divers, which
has not responded to our request for more information.
It's unlikely CO poisoning was the culprit since that would have been due to a faulty compressor
installation and affected more tanks. All the other divers appeared to have no problems.
It's more likely that the nitrox mix is suspect. This can happen especially if the nitrox is made
by partial pressure blending (when neat 02 is added to a tank and then
topped up with air) rather than de-nitrogenizing air through a membrane system. CO analyzers tend
to be expensive and complex to use- but anyone can buy a personal nitrox analyzer They can cost
around a couple of hundred dollars (Vandgraph, Divesoft, etc). Always check to know what you're
breathing- even if you think you're getting straight air.
- John Bantin
also_anon_dc
Contributor
The hypothesis put forth by the Undercurrent article doesn't seem to jibe with the Facebook post made by the rescuer. In that post she stated that the nitrox used by some of the divers that day tested at 35%. I suppose it's possible the O2 sensor was bad, but if so it was like that straight from the factory because she wrote that it was a new analyzer.
At 21m of depth, you get pO2=1.6 with nitrox 50%. There is lots of variability between individuals on oxygen toxicity resistance. You would probably need a higher pO2 to cause toxicity in a short time to two divers. I think it’s still more likely to have had a CO incident that 2 tanks with 70-80% O2.
I am surprised--shocked, to be honest--by the level of speculation in the Undercurrent article.
Yes me too. Not only it is speculative, but also doesn’t make sense. Also, it is possible to have some tanks tainted but not others. CO contamination is most likely IMO.
Undercurrent article is self-promotion - no additional facts.
OP
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Hello, John Bantin, you should know better than to publish this old myth...
As I mentioned earlier in this thread, the tanks may have been filled at different times, even different days, some while the compressor and filter were fine but two when the compressor was hot enough to burn its own oil or the filter clogged.
Thank you.
pauldw
Contributor
I'm assuming that where the lady says "atrial" bleeding she means "arterial" bleeding?
Would someone with actual medical expertise explain the pinpoint pupils on the already dead guy?
Would someone with actual medical expertise explain the pinpoint pupils on the already dead guy?
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