Carbon Monoxide tank risks and protections….

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DandyDon

Colonoscopy Advocate
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(This is relatively recent improvement in our sport, we’ve learned a lot together in recent years and still are learning, so I thought I’d offer my personal update. If you like it, you are welcome to reuse it without requesting permission.)

The subject of CO toxicity in tank air is getting more coverage than ever before with expanded knowledge as well as available and affordable 21st century technology, but not nearly enough. Instructors, other professionals, and old-time divers aren’t saying much, but that’s either from their training or their habits from before current technologies became so available, I think.

DAN is finally taking some actions but really needs to do more in educating divers about the risks and solutions, and I’d be writing a much shorter post here. Padi and other agencies are doing little to nothing. I guess this is more important to some here who may have personally known a diver who died from a tainted tank, or in my case are simply insulted that most fill stations will not spend pennies per tank to prevent the risks, operators are not spending 50c/day to make tank testers available to customers, and a few personal exposures I have documented.

DAN does admit that they have no idea how many drownings are caused by CO hits, how many clinical hits are just not reported to them, how many subclinical hits are shrugged off as traveler's-flu, etc. The US standard has long been a 10 ppm max while some countries are requiring maxes of 3 or 5, in part because the effect multiplies when you breathe it at depth, in part because of the binding properties, and more - and I've found readings over 5 ppm to be pretty common actually. I fumbled with my early testing from a make-do unit and no one to tell me how at first so I only got testing proficient a few trips ago, but I have turned a boat when I found 17! My last trip was with the new Analox portable analyzer and that was so much easier. A buddy pair can easily share the costs on one for a little over $300, and it'll last at least 2 years without service - much longer if not used every day and kept in a pelican box or similar, or bite the bullet like me as a solo traveler usually and just get one.

For an operator to provide the units and charge an extra dollar/tank for testing was suggested in discussion recently, but that would fail. Testing every tank can be boring after a few days of a trip when the tests are clean but it is all too easy for one tank in a lot to be dangerous so I keep it up. Most divers haven't read as much and will take a very erroneous attitude of "if yours is clean then I'm sure mine is" and skip the extra charge optional testing. No, the suppliers need to spend pennies a tank to ensure their air is clean, and the operators need to 50c/day so customers can confirm that. How long is may take for these practices to become common even in the Caribbean and Mexico is anyone's guess.

It was recently suggested that the risk was negligible, not enough to warrant divers taking actions - but a member with extensive experience on the subject offered good reason to think the risks are around 3-5%...
The risk of CO poisoning may be much higher than we'd like to admit basically because no one is doing a carboxyhemoglobin (COHb) in all dive fatalities, however if you look at the Dr. Caruso’s UHMS retrospective dive fatality abstract posted earlier 3 percent of the divers whose COHb concentration was checked at death had an anomalous level. Three percent is certainly well above the frequency one would expect for a potentially lethal contaminant that is "barely quantifiable" and far greater than the risk of dying from DCS.

We can also try and assess the frequency of CO contamination in our breathing air from another direction and that is by asking the compressed gas analytical laboratories what their frequency of test failure is for CO at the 10 ppm level. These labs receive thousands of dive air samples a month from fill stations all over the globe so this number would be the best real-time indicator as to the extent of the contamination problem.

This question was posed to the labs by Bob Rossier, an ex-NASA life support systems engineer, in 1998 and 2004 and reported in the DAN Diver Alert magazine. When Lawrence Factor and TRI Laboratories, two of the largest compressed gas laboratories in the USA, were contacted and asked the frequency of CO contamination in dive air alone (fire service compressed air has a CO failure rate about 0.1 %) both labs reported independently in 2004 that the failure rate was 3 to 5 percent, an incredibly high percentage considering the high toxicity of this contaminant and potential for death in the underwater environment. In 1998 these same lab directors were asked the CO failure rate in diver compressed air and reported it was 5 to 8 percent so things have improved somewhat since that time but not by much.

The point is though that if someone told you that there was a 5 percent chance the tank of dive air you might use could contain CO at a concentration above 10 ppm I think you would be hard pressed to call that "barely quantifiable" in fact a rationale person would request that their fill station install a CO monitor or that the individual diver would purchase a personal CO analyzer.

It does not surprise me at all that we are hearing of more and more CO-contaminated tanks plus CO-related injuries and deaths as the awareness of the problem and in-field tank testing has increased 100 fold with the availability personal CO analyzers. In the end the frequency of these CO incidents in the field should reflect the rate of CO contamination identified by the labs testing the compressed air from the same field on a daily basis. Only when a COHb concentration is done in all dive fatalities will we also see the frequency of anomalous COHb levels trend towards that 3 percent level.

In 2009 I spoke with these same lab directors again and they confirmed that nothing had changed since 2004 indicating that we in the dive community still have a 3 to 5 percent chance of receiving a tank of compressed air with CO contamination > 10 ppm. The samples sent to Lawrence Factor and TRI come from all over the world so this is a global dive industry problem but worse in those geographical regions where high ambient temperatures conspire to allow poor compressor installations to overheat and intermittently burn (autoignite) the compressor oil.

If it was reported that that our national blood supply contained HIV or Hep C contamination at a rate of 3 to 5 percent not only would the population be up in arms and demand rigorous testing to eliminate that risk, but I doubt you find to many potential transfusion recipients cavalierly saying this was a negligible risk and that they would rather forgo HIV or Hep C testing and just accept the risk of contracting a potentially lethal disease. Yet sadly in the dive industry that is exactly what we still hear today despite the facts indicating the CO contamination risk is quantifiable in our dive air and runs about 3 to 5 percent.

Sadly, the situation will not change much until more divers take actions, testing tanks, complaining about small readings, leaving boats after larger readings, and voting with their business as well as their reports here on SB. The portable Analox unit can be acquired at EII CO- Portable Carbon Monoxide Checker for as little as $325 including free shipping in the US, higher internationally and is a breeze to use tank after tank, T90 readings in 30 seconds. Turn the dial to field calibrate, blow in it to register a few digits and confirm it works (everyone’s breath contains a few points of CO), and go. Don’t bother with the bump gas offered.

There are other tank testing units, altho not really as desirable as Analox’s - unless one just cannot justify that much for personal trips. The Pocket CO will work and is available for $129 including US shipping at Pocket CO Carbon Monoxide Detector - Marv Golden Pilot Supplies. If I really liked it, I would not also own the Analox - but you can certainly use it for safety, and it's easy enough for a couple of divers. Here are my cautions and how-tos from my experiences and mistakes...
1: It is susceptible to contamination and misreadings from humidity and a variety of urban fumes, so stick it in a ziplock before you leave the plane and keep it in one. (I do wear mine turned on while sleeping on planes since none have their own and I think it'd be nice for someone to know if an onboard problem happens.)
2: Use slider, freezer grade gallon bags as they are easier to close, but take enough for a new one/day as they still tend to leak after handling.
3: Turn on the unit and crack the tank before sticking the bag to it less you learn how easy it is to blow one overboard if you hold the bag to the tank then open! That's how I learned. :blush:
4: When the bag is mostly full, close it, turn off the hissing tank, and start your stopwatch/SS timer. Wait 90 seconds or longer and read.
After your first trip, order the calibration kit in time to use it before your next. $39 plus shipping at Order the Pocket CO - Carbon Monoxide Detector Re-cal every 6 months for maximum accuracy. The can is only good for a year and 3 uses anyway, then replace.

The ToxiRAE 3 can be rigged to hook up to a low pressure hose for less than an Analox, or used in a slider bag for not much more than the Pocket CO with a fast response time, but I do not have a lot of info on it. It’s a viable choice, but I don’t like having to hook up a reg before testing and for a bag test unit - I can’t wear it discreetly on a plane or in a café. :crafty:

At what level do you refuse to breathe a tank? Pick a number between 3 & 15 - ppm, not % - then stick to it. Of the countries that do have regs, enforced or not, that's the range. Your call. For me now, I start complaining when I see 3 and getting off of the boat at 10. Some are less accepting of 3 to 5 ppm readings.

Ok, so what if you check every tank all week of a trip and get nothing. Haha, that did happen to me on my last trip after complaining to the operator about readings on my previous visit, so they do listen - and she was using a different provider. I was bored, but reassured, and kept testing. The first time you see 5-10 ppm should get your attention, more so for more. Next trip, same operator - who knows? See www.scubaboard.com/forums/basic-scuba-discussions/412257-so-do-you-get-bored-checking-tanks-co-when-you-never-get-readings.html

Am I a fanatic a about CO elsewhere in life? Well sure I am. My FB friends will confirm that easily. :laughing: For millennia of home, dugout or cave heating we coped with bad air trying to not kill ourselves, easiest in our sleep - but in recent decades home monitors have become so very cheap. People still die in every state so leaders and some legislatures are still trying to get a monitor in every home, but I like one in every bedroom, office, warehouse, café, vehicle, hotel room, etc. - and will carry my own anywhere. Not a problem at all. Lightweight and did I mention cheap…?

For divers, not so cheap - but until we can get all operators to take affordable actions to provide us with safe tanks, for the next couple of years at least - protect yourself…!!

Oh, and it does come up now and then about what my financial interest is in this? None, zilch, nada at all. I’ve spent more on this than I wanted to, but glad I did. :eyebrow:

thanks
 
Having been on a liveaboard where half the divers got sick, I have seen CO poisoning first hand and it is a serious problem that could easily kill someone. We had divers puking, and many others with severe headaches. That is way to close to the edge for comfort. Fortunately no one died, the boat owner rebuilt his compressors, and added CO analyzers.

At this point it is time to start hounding the local dive shops to upgrade their compressor systems with a continuous CO monitoring system. Not just their air tests done right after a filter change, and service. The costs are not expensive and it could save lives.

As I understand it some of the paramedics have started carrying CO analyzers on their persons so when they enter a home or business they are protected from a gas they can't see or smell, and in NY at one residence their alarms were screaming at them.
 
I thought I had bookmarked the page but alas I can't find it now. There was a thread here that had a litmus test for CO. You put it in a ziplock, blew air from the tank into the ziplock and if any was present the paper or capsule looking device would change colors. It was reusable until it detected the gas. It looked to be inexpensive. I wish I could find it again, i know I saw it here on scubaboard. Has anyone tried this type?

I know there are draeger tubes to detect CO and CO2. They are around $70 for a box of 15. That would make it more expensive than the electronic detectors in the long run.
 
Don, thanks for you in-depth report. As a recently certified diver I was aware of the CO issue but only academically. I just assumed that the people filling the tanks would be making sure that the air is good. My next dive trip is in May so decision time is fast approaching. Actually the decision has been made, I am getting an Analox. I keep waiting and hoping that someone will say "lets do a group purchase."

Thanks again and I appreciate your efforts in hammering this message home.
 
Having been on a liveaboard where half the divers got sick, I have seen CO poisoning first hand and it is a serious problem that could easily kill someone. We had divers puking, and many others with severe headaches. That is way to close to the edge for comfort. Fortunately no one died, the boat owner rebuilt his compressors, and added CO analyzers.

At this point it is time to start hounding the local dive shops to upgrade their compressor systems with a continuous CO monitoring system. Not just their air tests done right after a filter change, and service. The costs are not expensive and it could save lives.

As I understand it some of the paramedics have started carrying CO analyzers on their persons so when they enter a home or business they are protected from a gas they can't see or smell, and in NY at one residence their alarms were screaming at them.
And taking enough pride in their product to offer the use of tank testers, too! Yeah, firemen and paramedics are frequently carrying CO alarms. Google News the subject and you'll see many stories.

Doesn't California require home monitors? 5 people taken to hospitals for carbon-monoxide poisoning

Keyless ignitions are supposed to auto-off after 10 minutes, but sometimes don't: Keyless Mercedes linked to carbon monoxide poisoning in West Boca, authorities say - Orlando Sentinel

Job safety often misses CO needs: RANCHO CUCAMONGA: Carbon monoxide poisoning possible in painters

Their alarm worked: Family avoids gas leak death (From Your Local Guardian)

Well, there are many just from the last 24 hours...

I thought I had bookmarked the page but alas I can't find it now. There was a thread here that had a litmus test for CO. You put it in a ziplock, blew air from the tank into the ziplock and if any was present the paper or capsule looking device would change colors. It was reusable until it detected the gas. It looked to be inexpensive. I wish I could find it again, i know I saw it here on scubaboard. Has anyone tried this type?

I know there are draeger tubes to detect CO and CO2. They are around $70 for a box of 15. That would make it more expensive than the electronic detectors in the long run.
Co-Pro. I looked at it early in my investigations, found it discontinued, but I guess it was revived. After a week of messing with condoms you'll be ready for a real unit, I think - but lets us know? They are not accurate, but better than nothing.
 
And taking enough pride in their product to offer the use of tank testers, too! Yeah, firemen and paramedics are frequently carrying CO alarms. Google News the subject and you'll see many stories.

Doesn't California require home monitors? 5 people taken to hospitals for carbon-monoxide poisoning

Keyless ignitions are supposed to auto-off after 10 minutes, but sometimes don't: Keyless Mercedes linked to carbon monoxide poisoning in West Boca, authorities say - Orlando Sentinel

Job safety often misses CO needs: RANCHO CUCAMONGA: Carbon monoxide poisoning possible in painters

Their alarm worked: Family avoids gas leak death (From Your Local Guardian)

Well, there are many just from the last 24 hours...

This family in Colorado won a weekend in Vail in a newly built home as a prize. Because of improper venting the family was killed by Carbon Monoxide, very tragic. Colorado requires new builds to have CO detectors now.

Faulty Heating Connection Leads to Carbon Monoxide Death of Family - ABC News
 
DandyDon,

Without your many insightful threads and posts regarding CO levels in divers' gas I would never have even considered CO poisoning a potential problem. I'm glad that your being a stickler for safety has been able to bring CO poisoning to the attention of so many recreational divers, and dive centres.
My dive club has O2 analysers but I doubt anyone has ever considered the importance of analysing CO levels when using an unfamiliar (or even regular) dive operator.

Nic
 
If we're trying to collect hard data in this thread, I'd like to suggest the 1998 DAN paper someone (sorry, can't remember who or where) posted in one of the recent CO discussion: CO Poisoning in Recreational Diving

Of the 67 fatalities they found where blood CO levels had been tested, 2 (3%) showed medically significant amounts (my words) of CO, including one where CO poisoning had not been suspected before the autopsy.

The number of cases seems a bit small for statistical accuracy, but suggests on the one hand that CO contributes to the cause of death in a minority of fatalities, but on the other hand, is a lot more often than 'very infrequent' and therefore deserves some attention.

From this data, it doesn't seem possible to say with any significant confidence how often CO may contribute to non-fatal accidents or near-misses, although one might guess that it's more often than the fatality rate, since presence of significant amounts of CO would tend to make a diver feel off or sick enough to bail out before things get catastrophic.

One other possible correlation is that 3% of fatalities rate is similar to the 3-5% CO test failure rate quoted in DD's original post. This statement does not necessarily imply cause or effect, but the numbers are similar enough that seeing if there's a relationship may be one area of additional research.
 
I wonder, if it's 3-5% in countries that mandate air testing, and as such would have a reasonable level of "compressor care" by the owner, how high do you reckon it would be in countries without mandatory regular testing?
 

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