Update: Now I Have a Personal Carbon Monoxide Monitor/Tester

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In Belize I wondered about the condition of some of the compressors. When I asked about it...
Good for you to ask. I don't think many do; I didn't until I heard a first hand description of the Roatan compressor that killed a Texas tourist and popular, local DM two years ago. Even then, it took me a while to build up to this - not realizing how wide spread the risk is. I've taken the rest of your post out to try to answer in parts...

the dive masters (who, despite living in a developing country are neither stupid nor uneducated) told me that their compressors regularly checked by PADI. They're supposed send air samples into TA or another qualified lab quarterly and maintain records, but there is no enforcement. I have to wonder about the truthfulness in them actually knowing or just repeating what they heard? Even if a resort had a monitor alarm that the compressor was putting out 12 ppm CO; the show must go on, the resort guests must dive, and the DM has to feed his family at the end of the day - so how much rationalizing could happen?

BTW, I have only been to Belize tonce, dived with two operators, didn't know about this problem then: one operator there did show me his compressor and records tho and has posted here recently that he still tests and records, but doesn't bother telling Padi; the other - I would never think about diving with again.

Not only that, but the dive masters themselves, who use those those compressors daily, have a very good incentive to ensure they are maintained properly. In other words, in many cases the guy who maintains the compressor is also the guy who breathes the most air from it. Well, yes - as was the case for the Roatan DM killed in 2006, the Maldives DM severely injured recently as discussed in this thread http://www.scubaboard.com/forums/ac...ed-baani-adventurer-maldives-liveaboards.html and so on. I really don't think that many of those DMs would go on strike if the testing wasn't done and the compressors weren't kept spotless.

Having said that, judging from the outward appearance of some of these compressors, anyone would question the air quality. You did look at some? What did you see? If you saw any oil leaks, congratulations for being alive.

I wonder:

1. What does DAN say about this?
As I mentioned in post #1: Excerpted from Alert Diver Article: CO Monitors - a carbon monoxide detector can save your life May / June 1998 Issue, By: Robert N. Rossier

“Most states and municipalities do not require testing of a diver's air in the event of a fatality. The autopsy findings of a drowning victim are non-specific, and the presumed cause of death is often based on circumstantial evidence. Routine toxicological studies performed at autopsy do not include a measure of CO blood or tissue levels. Unless CO poisoning is suspected, usually no tests are made to determine levels in the body or the amount in the diver's breathing-gas cylinder. These facts point to the question of how many other diving fatalities might actually involve CO poisoning as a contributing factor.”

DAN members may login to see the entire article here: Divers Alert Network : Alert Diver Articles

If you'd drowned in Belize, it's just not likely that you or the tank air would be checked, and even if they were and CO found - like the Roatan case, you'd never read about it. Tourism cannot be discouraged.

2. How come there isn't a purpose-built SCUBA tank CO detector? Sometimes the trash bag that I always carry around with me gets a hole in it. I suppose because the market pressure is always about cutting prices reasonably, so Padi passed the buck by requiring Padi operators to test their compressor air and keep records - no enforcement, no requirement to use an inline monitor with auto shut-off, nothing else I know of, and I have been looking, reading, discussing, whining, even calling Padi. I suppose I may have missed something, but then - maybe not.

Looking over the most recent 2007 DAN Diving Report on 2005 injuries and deaths https://www.diversalertnetwork.org/medical/report/index.asp , of the 89 US & Canadian citizens whose deaths were reported to DAN, most of those died in US & Canadian waters. But looking at the cause of death for all reported everywhere, over 50% drowned, some unknown, some written off as Sudden Death, and even of the Cardiac cases - who knows. No one knows how many died with CO being the root cause, much less how many cases of "vacation flu" and "travelers illness" may have been caused by this largely unmonitored risk.

Okay, there is certainly a chance that I may be over estimating the risk. Even tho many (most) tropical operators do not test and do not run CO monitors with auto shut off, maybe the end result is still a low numbers of deaths and injuries as the compressor operators probably do a good job. Well, that's not enough for me to feel comfortable at depth, so I will be double checking my air for CO just like I double check my Nitrox for O2.

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Pteranodon I am not sure I follow your logic here as CO being a gaseous contaminant in the breathing air follows the same partial pressure rules as any other individual component in the gas mixture (i.e O2, N2, CO, CO2, CH4, etc.)

If there is 10 ppm CO measured at 1 atmosphere in the lab or with a hand held detector the surface effective concentration at 5 ATA will be 50 ppm and the clinical effects at this depth will be similar to a person sitting in a chair on surface exposed to 50 ppm. In reality these clinical effects will be enhanced at depth due to exertion, increased CO2 due to equipment dead space, etc.

In terms of the physiology of CO poisoning it is now understand that the toxicological effects are not just from the binding of CO to hemoglobin to create a chemical anemia, but in addition a significant proportion of the effects are a direct effect of CO on the energy-producing enzyme chains in the cell's mitochondria. These effects are not easily reversed with oxygen which is the topic of much current research.

Here is a good summary article on CO in Diving by Gavin Anthony published in May 2007.
http://www.analox.net/site/content_pdfs/CarbonMonoxideInDiving.pdf

Of interest is the new British Health and Safety Executive Diving Information Sheet which was published this week. It applies to air diving to 50 metres. Of note is the maximum recommended CO exposure is 3 ppm across the entire dive population. Also the recommendation to install an inline CO detector on the compressor and to have a catalytic bed in the purifier.
http://www.hse.gov.uk/pubns/dvis9.pdf

Recall a young fit non-smoking Navy Seal can tolerate a higher exposure level than an older, obese, unfit, smoker. The levels are set for the most sensitive person in the exposure group.

Don thanks for posting the new CO monitor.


I knew I should have waited for you to show up on this thread. Oh well, I was going in the right direction anyway.
 
Don I have not read all of the responses just curious. What would you expect the response to be at a resort if you found a tank that set off the alarm? Would you start testing more tanks? Ask for a second check?
 
Second check? Like they would have a way to test a tank?

I'm sure that I'd not dive that tank or even let my reg get contaminated by it as well as let Everyone know about it. I wonder how many on a boat would still go out if they knew I wasn't because my CO monitor tested positive? I guess we'd see how well the operator dealt with the situation, take good notes, spell names right, start writing my various reports in my head as I sought other diving opportunities. You'd probly see it here before I left the resort.

Any suggestions...?!

Does your regular fill station use a monitor like this? What if the resort you flew to didn't...?
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...You did look at some? What did you see?

The most memorable one was a diesel-powered compressor (no electricity on the island) where the whole exhaust system had rusted off at the manifold, none of the gauges worked, and the guy had to bang on the crankcase with a wrench to get the thing started. No cylinder bank, he just filled the dive cylinders directly off the compressor, and when it was running everybody on the island knew it, because it was so loud.

This was also one of the most knowledgeable, ecologically aware, and capable dive guides I've ever dived with, and the dives were fantastic.

I'd still rather have my own gauge. Can't find it in the budget any time soon, but if I was gearing up for another trip abroad I think I'd find the money.
 
DandyDon,
You know I never really thought about using one before reading your post. For the price of one day of diving, I could save my life. Hmmmm nothing to think about I guess you did the research for us so I am looking into placing an order. Thanks for sharing the info.
 
The most memorable one was a diesel-powered compressor (no electricity on the island) where the whole exhaust system had rusted off at the manifold, none of the gauges worked, and the guy had to bang on the crankcase with a wrench to get the thing started. No cylinder bank, he just filled the dive cylinders directly off the compressor, and when it was running everybody on the island knew it, because it was so loud.

This was also one of the most knowledgeable, ecologically aware, and capable dive guides I've ever dived with, and the dives were fantastic.

I'd still rather have my own gauge. Can't find it in the budget any time soon, but if I was gearing up for another trip abroad I think I'd find the money.
speechless-smiley-012.gif
Oh My Gawd...!

Diesel powered are much more at risk than electric. Having your tank filled first off of a newly started compressor would be safest. You were on the atoll to dive and not much choice - dive that air or not. I don't guess you remember a wall monitor as illustrated above?

Yeah, I'd budget this gizmo into my next trip, but then - I already have.

Try this everyone - I've done it...


Email the next operator you plan to dive with, asking them if they are affiliated with Padi, and if so - to please email you a copy of the latest quarterly air test results as required by the agency.

Also ask them exactly which CO monitor they use on their compressors and if they have automatic shut-offs - and at what point. Tell them you'll be looking forward to touring their fill area.

Let me know how that goes...
:eyebrow:
 
Dandy Don,
Thanks for the info and links on the Pocket CO detector. I was a victim of bad air once and that was enough for me. I contacted the company for some info on diver use and was satisfied with what they told me on how to test a tank of air with the device. Will have to stock up on zip lock bags!!!
I'm ordering one tonite!
Info like this makes the SB a great place!
Jeff O'Brien aka Ocean One
 
I'm sure that I'd not dive that tank or even let my reg get contaminated by it as well as let Everyone know about it.

Being less than educated in the ways of CO contamination, forgive me if my question sounds silly.

If your reg were "contaminated" wouldn't it simply be solved by blowing a little "clean" air through it? Does CO adhere to all parts and stay for a long time?

Does nitrox make a difference? Example: Your CO reading is X and you know that in standard air, you'll experience the listed symptoms in the chart after the given time because it deprives you of oxygen. I read that CO attaches to hemoglobin more readily than O2. However, if pure oxygen will flush out excess CO, wouldn't Nitrox slow/reduce the contamination?

If you got the recommended maximum number listed on that chart but you're diving with higher amounts of oxygen, wouldn't there be some degree of offset? I'm assuming those numbers all reflect CO readings in standard air. I wonder what the maximum allowable would be if they tested conditions in which greater percentages of o2 were present.

Lastly, don't misinterpret this post....I clearly see the benefits of testing/monitoring. Just using this to get learned. ;-)
 
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