Thanks for the report. CO is simply a weak point is overall scuba air quality, too easy to happen & and cannot be discovered without testing, none of the agencies or even DAN are doing much, so it's going to continue to be a constant risk - anywhere.
I second that, but, aren't all the fills on the island from the same place?
Nope, there is the biggest supplier who provides almost all of the Nitrox, but there are several compressors.
Given that only a tiny fraction of divers test their tanks for CO, yet no one actually seems to get harmed by CO levels in their air...
Fail, false, caca talk...
People probably breathe CO all of the time and just don't realize it. They probably assume their headache is from the sun or fatigue, etc. CO poisoning is a combination of exposure time and partial pressure, maybe the shallow profiles here help keep more people alive. We've dove 11 tanks on the island this week and all tested 0ppm, until today. All of the tanks that had CO in them were nitrox tanks that were filled on 03/05 (they are labeled) at Meridiano 87. It is my understanding from asking around that they are the only source of nitrox on the island. We did find 4ppm in an air tank when we were diving the cenotes on Sunday, so CO is out there, not just on Cozumel.
Yep, so little is done to monitor the risk, we just have little knowledge of how many subclinical CO hits are accepted as travelers flu, etc.
For this very reason Aldora has its own compressor shop and makes nitrox by the membrane method, using state of the art CO monitoring systems. We do fills for other shops as well.
Dave Dillehay
Aldora Divers
I'd still test your tanks too, why not, but I'd expect yours to be the cleanest. We have discussed this extensively and I'd be amazed to find a failure from your tanks, but testing remains the only guarantee.
Scuba Club Cozumel does their own fills.
Many compress air, but very few produce Nitrox - and I doubt that they do.
Thanks, Dave. I knew Aldora does its own fills. One of the reasons I dive with you. Just for everyone's information, ProDive Mexico at Allegro has their own fill station as well. They do not use Meridiano, either.
You think they make their own Nitrox? To do so, the compressor has to produce O2 clean air for safe partial pressure blending like Meridiano, or be a special compressor that makes nitrox by the membrane method like Dave's. I have a hunch they get those tanks from Meridiano...?
Seriously?
1. Was that ever proven to be from CO poisoning?
2. One death out the hundreds of thousands of dives that likely occurred on the island since then makes it statistically insignificant in my book. In fact, the hundreds of thousands of successful dives since then show exactly how benign small undetected CO levels are since no one else has died in the meantime. The incidence of DCS is far higher, yet we continue to dive. Why address a risk when it's so infinitesimal while we don't address the much greater risk of DCS by not diving at all?
"As best I know NO ONE has died from CO in Cozumel. An old story, about a year ago, several divers got "sick" from bad air from Dive Palancar who had been filling their own tanks. Yes, I see the wisdom of checking air quality or having great confidence in your air supplier and I personally have done a LOT to make sure that is the case.
"What has happened to this thread is near paranoia and causing many people to reconsider coming to Cozumel to dive--while I am completely convinced, from lots of experience around the world, that Cozumel is perhaps the world's safest dive location from just about any perspective." -- Dave Dillehay, 11/18/2011
Dave is a wise man who changes his mind given sufficient facts suggesting such. Can't say as much for you. Yes, it was confirmed as a CO death. We do not know how many drownings were triggered by CO over the years. DCS is a risk the diver has a number of options to avoid, but unknown CO levels in tanks are a totally unacceptable risk that the diver has no options, other than testing his tanks. You don't want to bother, fine - but why do you insist on interrupting constructive discussions with your hogwash...?!
Oh, that's just your style, I think you've explained.
But Meridiano has CO monitors installed now, don't they? So wouldn't that make the other self-filling shops (besides Aldora, which also monitors CO) actually more dangerous?
They did, I guess they still do, but last I heard when I asked - they didn't have auto cutoff installed. What happens if their alarms go off, who knows - if the equipment has been maintained correctly? It's not their first failure since they got them.
ScubaDoc says 10ppm
"Carbon monoxide in diving is the product of incomplete combustion of hydrocarbons and is usually from compressors and cigarette smoking. In addition to the effect on the hemoglobin molecule, it has a toxic effect on the cytochrome A3 system. Prevention requires periodic air sampling. The maximal allowable level is 10 ppm (0.001%)."
http://www.scuba-doc.com/carbonmon.html
That's one opinion. Some authorities & countries have lower limits. How CO injures a diver under pressure, and more so on ascent is tricky, so it's hard to say what a safe level is.
Beyond that, CO is one of the few possible contaminants we can now test for, so if they allow that in - what else is getting in that we cannot test for. Fill stations should provide clean & non-toxic air. Any failure is a reflection of negligence.
And the more of us who do test, cancels dives over failures, and reports openly - the better the situation will get in the diving world. Keep the pressure on as few care otherwise. :medal:
