Cozumel Diving 2/26/12 - Had one tank read 12 ppm CO -

[Insta-Gator]

Is the Analox easiest to use? I'm familiar with them for Nitrox. Is there a thread comparing the various CO analyzers?

EII CO Carbon Monoxide Analyzer: Analox - Looking after the air you breathe.

 

[jbtut]

This is an interesting article from the similar Coz thread discussing this issue. | Medicine & Science - take care for your health So if I understand correctly, the approximate level of 3000 ppm of CO would be knock a diver into uncoscienceness. I'm guessing this is not an absolute number but approximate. Should you get a bad tank with 20 ppm of CO and dive to 100 ft I am wondering what noticeable effects ,if any,you would experience post dive. At depth you would be exposed to 80 ppm. If a smoker has about 400 ppm of CO at the surface,I would guess you would feel much better after the dive than he/she would even if they had a tank with 0 ppm. Where is my logic flawed here?

I believe there's a bit more to the equation than simply looking at PPM equivalent at depth. There is also an issue of how the CO is absorbed under pressure. CO will attach to hemoglobin much easier than Oxygen. My general understanding is that at depth, the oxygen concentration is greater, meaning that even with your blood absorbing more CO than it might at the surface, you are still getting oxygenated blood circulating very well. As you surface and the o2 pressure drops, the built up CO remains and you enter a state of less oxygenated blood. That's when the health effects show up, and why most CO incidents involve passing out at the end of the dive.

With respect to the smoker, they aren't breathing smoke continuously for an hour. If they did, I think there is a good likelihood that they would sustain anoxic brain injury. I'm not sure a human could survive pure cigarette smoke for an hour.

It may be the case that the 10ppm is a very conservative number and 30ppm is still safe depending on depth and length of time at depth. It would be interesting to read about why the decision to set 10ppm for grade E air was set at that amount.

 

[DandyDon]

So now it's not even a risk of death, just a risk of getting sick? Then I'll respect the advice to purchase and use a CO analyzer with the same weight that I apply the advice to not eat salads or undercooked meats and fish in Mexico.

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This is an interesting article from the similar Coz thread discussing this issue. | Medicine & Science - take care for your health So if I understand correctly, the approximate level of 3000 ppm of CO would be knock a diver into uncoscienceness. I'm guessing this is not an absolute number but approximate. Should you get a bad tank with 20 ppm of CO and dive to 100 ft I am wondering what noticeable effects ,if any,you would experience post dive. At depth you would be exposed to 80 ppm. If a smoker has about 400 ppm of CO at the surface,I would guess you would feel much better after the dive than he/she would even if they had a tank with 0 ppm. Where is my logic flawed here?

Looks like an interesting article. Not entirely correct in some areas but I don't want to go on and on here. His suggestion that the compressor problem is nearly gone is a bit too optimistic for me. I do like his explanation on the complexities of CO poisoning as it does have something of a snowball effect. Where he got 3000 is a mystery tho? This chart Risks of Carbon Monoxide poisoning is more accurate I think.

And no, a smoker does not have 400 in his lungs at surface. Smoking is bad, but a typical smoker will blow around 10 ppm from his lungs; we know that from our own equipment testing. Not defending smoking, but smokers do have richer blood in that the body will produce that in partial reaction to smoking. Ask your blood bank.

Is the Analox easiest to use? I'm familiar with them for Nitrox. Is there a thread comparing the various CO analyzers?

EII CO Carbon Monoxide Analyzer: Analox - Looking after the air you breathe.

I don't think we've had a recent thread about CO personal analyzers lately or an objective comparison. That would be a great dive magazine article huh, but I guess comparing regs, etc. is more profitable. Yes, the Analox seems to be the easiest to use, best backed by manufacturer, best features, etc. I own the cheaper Pocket CO as well, but it's a pain to use. The Toxirae 3 choice is is a good one, altho most who use it also get the parts to hook it to the low pressure hose for flow thru reading - and then for that much, the Analox is more appealing. There are a few others but not worth mentioning in my opinion.

I believe there's a bit more to the equation than simply looking at PPM equivalent at depth. There is also an issue of how the CO is absorbed under pressure. CO will attach to hemoglobin much easier than Oxygen. My general understanding is that at depth, the oxygen concentration is greater, meaning that even with your blood absorbing more CO than it might at the surface, you are still getting oxygenated blood circulating very well. As you surface and the o2 pressure drops, the built up CO remains and you enter a state of less oxygenated blood. That's when the health effects show up, and why most CO incidents involve passing out at the end of the dive.

With respect to the smoker, they aren't breathing smoke continuously for an hour. If they did, I think there is a good likelihood that they would sustain anoxic brain injury. I'm not sure a human could survive pure cigarette smoke for an hour.

It may be the case that the 10ppm is a very conservative number and 30ppm is still safe depending on depth and length of time at depth. It would be interesting to read about why the decision to set 10ppm for grade E air was set at that amount.

Yep, the partial pressure of CO at depth is only a part of it, the brain sending more blood to the heart and brain in reaction to the toxicity, CO binding to the hemoglobin and staying even while PPO decreases, severe damage to blood cells, and more. Of the countries that set maximums for CO in scuba air, the US and some others are at 10, some at 5, some at 3. I think 10 should be the max to even consider, but there is no reason why the compressors should produce more than 3. Available equipment and technology has changed dramatically even since I started scuba, much less when the old timers developed our sport - and some are just not up to date.

An Analox Clear inline monitor with auto cut-off is not cheap* but over thousands of tanks it is, just pennies, so then the only reason for not running one is it can slow down production. Some fill stations would rather run the machines hot and hope they don't kill anyone. Mexico has no regulations that I know of, and even if they did - well.

* Except that DAN & Analox are donating 10 units to some Quintana Roo Ops, altho I don't know which? Won't change my approach tho, as I don't trust anyone to certify my air. I'll test, TY.

 

[TomZ]

The Analox CO tester is very easy to use. I have an Oxycheq El Cheapo II Oxygen tester with the BC hose restrictor. I test for oxygen percentage, then unscrew the oxygen sensor off the black plastic dome and put it on the CO dome to get a reading (hopefuly zero!). It's quick, easy, and only uses a tiny bit of gas.

 

[Mossman]

True, there are probably 1000's of dives going on to 100' and deeper, and no one dies. And yes, it will take much more than 12ppm, my point was CO present in a tank is a red flag, so why take the risk when the technology is available and relatively inexpensive? It is all personal choice, I know. And as far as getting your annual service, I have heard that some operators are beginning to require proof of a service in the past year on your personal equipment or you don't dive on it. A regulator is a life support system, I don't feel like taking a chance.

Proof of service? What do you have to do, carry around your old o-rings?

An iron lung is a life-support system. A reg is just a way to breathe underwater at depth.

 

[stevep4444]

Some good info and opinions in the thread.After due consideration my view is ,even with all reasonable precautions, everytime I choose to go diving their is a risk involved. I accept that because I love to dive. I also am convinced that I have a much higher chance of having a serious or deadly accident while driving in my car and while I usually wear a seatbelt I will not wear a helmet even though it probably increases my outcome should something bad happen. Also, I am not going to wear a snorkel vest on the dive boat on the way to the dive site and I don't carry a GPS while diving in Cozumel.
People who dive while in poor physical condition,are overweight,smoke,drink heavily while on a dive vacation,get too much sun and don't stay properly hydrated are taking much more risk than me diving a tank with 20 ppm of CO and diving within recreational limits.
Call me crazy,but to each his/her own.

[TD="width: 59%"] Table 2: Air concentrations and acute health effects of carbon monoxide
Concentration (ppm)
Health Effects
Less than 50
Mild headache
50 to 200
Severe headache
200 to 400
Weakness, dizziness, nausea, fainting
400 to 1200
Increased/irregular heartbeat
1200 to 2000
Loss of consciousness, death
2000 to 5000
Death may occur in minutes
Note: At very high levels of exposure (> 5000 ppm), death from cardiac arrhythmia can occur before there is a rise in blood COHb levels.
[FONT=Times New Roman,Times New Roman] [FONT=Times New Roman,Times New Roman]Workers who smoke should be aware that smoking a pack of cigarettes a day, with no other carbon monoxide exposure, creates a level of 5 to 6 per cent of COHb in the blood. Heavy cigar smokers can reach up to 20 per cent.
A pregnant worker who may be exposed to carbon monoxide at the work site should consult a physician. Carbon monoxide crosses the placenta and clears from the blood of a fetus at a much slower rate. As a result, a fetus is at a higher risk for health effects compared to the mother. The employer should remove the pregnant worker from exposure.
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[DandyDon]

 

[jbtut]

Some good info and opinions in the thread.After due consideration my view is ,even with all reasonable precautions, everytime I choose to go diving their is a risk involved. I accept that because I love to dive. I also am convinced that I have a much higher chance of having a serious or deadly accident while driving in my car and while I usually wear a seatbelt I will not wear a helmet even though it probably increases my outcome should something bad happen. Also, I am not going to wear a snorkel vest on the dive boat on the way to the dive site and I don't carry a GPS while diving in Cozumel.
People who dive while in poor physical condition,are overweight,smoke,drink heavily while on a dive vacation,get too much sun and don't stay properly hydrated are taking much more risk than me diving a tank with 20 ppm of CO and diving within recreational limits.
Call me crazy,but to each his/her own.

Is it fair to assume that you don't check your nitrox mix either? If you do I'd be interested in the logic of checking the mix but not the CO.

 

[stevep4444]

Yes I do check nitrox. I would compare it like this. I wear a seatbelt while driving a car but don't wear a helmet. Do you wear a helmet while driving your car? It is safer isn't it?

We each draw the line within our own comfort level. Your choice. Enjoy your day!

 

[DandyDon]

Is it fair to assume that you don't check your nitrox mix either? If you do I'd be interested in the logic of checking the mix but not the CO.

If diver was going to skip testing one, it'd be more logical to skip the O2 since someone has tested and marked it huh? I have seen Coz divers picked up at a dock on the way who dived Nitrox without testing. I won't, but some do.

Yes I do check nitrox. I would compare it like this. I wear a seatbelt while driving a car but don't wear a helmet. Do you wear a helmet while driving your car? It is safer isn't it?

Not the same at all. Testing a tank takes a few seconds, and you compare that to wearing a helmet for the entire drive?

We each draw the line within our own comfort level. Your choice. Enjoy your day!

Sure, we'll all agree to that. Your call for your dives.

I remember a trip to Roatan with a nice group, none of us liked the O2 analyzer at the dock, but out of 15 or so divers - only 2 of us owned our own O2 testers - and my battery died.

We all borrowed the good one. Even tho I was finding 5 ppm in my tanks then tho, no one wanted to borrow my CO tester. Each to his own. I've seen divers leave by ambulance several times and it didn't stop my diving.