Continued Carbon Monoxide - Cozumel

[DandyDon]

Well, I have felt like I was beating a non-living equine at times, as well as being a boat spectacle when I was the only one testing - but the latter doesn't bother me. I'll still wear my inflatable vest on moving dive boats regardless of who snickers as well as a big pony on dives so I'm cool with being the odd man onboard at times. I've survived plenty of my own screw-ups so trying to cut back on risks, and if you can't trust the air they put in your lungs at depth...?

I was surprised at first with the hard resistance I got from one Coz Op but then came to see it, and two members have PMed with correct guesses on who it was based on the tone of the little info I gave. I don't know how other Coz Ops feel about the news which is surely spreading across the island some at least, from this discussion being read by some, from the testing we did on the boat, the words I had with the Op I used & liked, all so soon after the injuries incurred at one of the former top islands Ops with his own compressor - I suspect a wide variety of reactions, but I don't think they can ignore us for long. Coz is a popular destination and as they see more and more testing done on their boats, as well as hear complaints and even refusals to dive - just maybe they will spend a few pennies a tank to clean up their act. They may still try to sweep this under the rug, but maybe they'll get the message this time?

He was not the first Op I talked with who did not realize that electric compressors can create their own CO, as well as intake it in some situations. See http://archive.rubicon-foundation.org/7964 This part was especially interesting...

Another phenomenon may be behind some previously unexplained episodes of underwater incapacitation and perhaps death: low-level CO poisoning and/or the effects of gaseous contaminants generated within the compressor, including toluene and other volatile compounds. Many low molecular weight volatile contaminants are anaesthetic and will be potentiated by pressure and nitrogen narcosis. In sub-anaesthetic doses, impaired judgement, lowered seizure threshold and sensitisation of the heart to arrhythmias may occur. Toxic compounds can be volatilised from some compressor oils, especially mineral oils, in overheated compressors, or be created de novo under certain combinations of temperature, humidity and pressure, perhaps catalysed by metal traces from compressor wear and tear. Most volatiles can be removed by activated carbon filtration but many filters are undersized and may overload in hot, moist conditions and with short dwell times. A compressor that passes normal testing could contaminate one or more cylinders after heating up and then return to producing clean air as the filters dry and the systems cool. The scope of this problem is very unclear as air quality is tested infrequently and often inadequately, even after fatalities. More research is needed as well as better education regarding the safe operation and limitations of high-pressure breathing air compressors.

It won't stop with inline monitors and filters tho, as those must be maintained correctly, on time, etc - and testing should continue even with compressor room tours and and pics of the monitors. Tanks are borrowed at times, other possibilities exist, and besides - it's just a good habit to get into for this age of air bags, seat belt acceptance, tighter security at many other angles, etc.

And then there is the rest of the Latin America & Caribbean Area so dear to us diving Americans and most of the rest of the diving world. Any serious diver who owns his own gear really should own & use his/her own CO tester, regardless of the supplier - unless probably-safe is good enough for the individual, except I wonder about even that being totally true. How many divers have you seen ill on dive trips?

And I hope that more divers will publicly post their findings here on SB. If we don't want government regulation here, and can't trust that anywhere elsewhere, we have got to help ourselves.

thanks​

 

[WOODMAN]

Okay, that does it. I've finally pulled my head out of the sand and ordered my own personal Pocket CO2 Scuba test kit, and hereby pledge to use it. :signofcross: I can't believe it took me this long to pay attention to what seems like a glaring hole in the otherwise notoriously anal safety mindset that usually characterizes scuba in general. When I reflect back on the number of people I have seen who were suspiciously sick right after a dive, with no real reason for it, and who felt much better after resting and breathing fresh air for awhile, it really makes you think. Yeah, there are about a dozen other reasons for this to have happened, but... you gotta wonder. So, now I will join the sparse (so far) ranks of those who test their gas for CO2, as least on an intermittent basis, anyway. The first few tanks on a trip for sure, and periodically thereafter as we see how it goes. Thanks for the heads up, Don, and keep up the good fight. Woody

 

[Shasta_man]

Note that you can get carbon monoxide poisoning from other sources besides the tanks. Depending on the design of the dive boat, you can get it from outboard engines on the dive boat out to the site. The aluminum hulled ocean going speedboat used by one of the dive ops in Taveuni Fiji zapped my wife. The boat had benches with tanks down the sides, and had a roof covering with a windshield. At speed, the passenger area with the windshield and roof made a low pressure area in front of the 150 HP outboard engines. That meant that the exhaust just swirled right back into the passenger area. Opening the center of the windsheild would have blown the exhaust right out the back, but traveling with it closed resulted in carbon monoxide flowing back into the passenger area. The dive guides were well aware of it and always stood in the wind at the very back of the boat.

It happened to us on day one and then we took it again on day two, and I was aware and tall enough to stick my head above the tanks on the side and out into the wind to get fresh air. However, it reduced my wife in about 15 minutes to a blubbering, spitting idiot. They dropped us at the island which was the SI spot and she laid on the beach, literally, for 15 minutes before she felt good enough to get up.

 

[swamp diver]

Note that you can get carbon monoxide poisoning from other sources besides the tanks. Depending on the design of the dive boat, you can get it from outboard engines on the dive boat out to the site. The aluminum hulled ocean going speedboat used by one of the dive ops in Taveuni Fiji zapped my wife. The boat had benches with tanks down the sides, and had a roof covering with a windshield. At speed, the passenger area with the windshield and roof made a low pressure area in front of the 150 HP outboard engines. That meant that the exhaust just swirled right back into the passenger area. Opening the center of the windsheild would have blown the exhaust right out the back, but traveling with it closed resulted in carbon monoxide flowing back into the passenger area. The dive guides were well aware of it and always stood in the wind at the very back of the boat.

It happened to us on day one and then we took it again on day two, and I was aware and tall enough to stick my head above the tanks on the side and out into the wind to get fresh air. However, it reduced my wife in about 15 minutes to a blubbering, spitting idiot. They dropped us at the island which was the SI spot and she laid on the beach, literally, for 15 minutes before she felt good enough to get up.

This is a very common problem in the dive industry as well and often overlooked source of CO contamination prior to jumping in the water. Another benefit of having a portable CO monitor on board is one can prevent exposure to CO from this station wagon effect you describe which has poisoned at least 879 boaters in the US from 1990 to 2009 and resulted in 160 fatalities.

One can read about this issue by following the link labeled Idaho 2009 MAC Meeting: Carbon Monoxide Poisonings below and the individual case details of the poisonings by state under April 2008 National Case Listings
Double Angel Foundation - Project UpdatesF

The highest risk boat is the "express cruiser" with inboard gas engines where divers can be easily incapacitated in minutes if in the death zone while the engines are running. CO concentrations even 10 feet out from the transom can be several thousand ppm.

There are many parallels with the way the CO in boats problem went unnoticed for years despite a handful of advocates showing there was an epidemic of drownings related to CO and the fact the US compressed breathing air laboratories have shown for a decade that the rate of CO contamination in dive air samples submitted is somewhere between 3 to 8 percent. The labs are finding CO contamination so it is no surprise individual divers are confirming this fact in the field by using portable measuring devices.

There are some words of wisdom in the first presentation which may have some relevance to the CO in dive air problem:

"Why wasn't the problem identified earlier? Because it's unbelievable.

We only see what we look for and we only look for what we know."


The first step needed to identify the extent of the CO in dive air problem is for divers to begin looking and to measure their dive air for contamination using portable CO monitors, and secondly to accept that CO contamination from overheated electric compressors is not so unbelievable.

 

[cruiser]

Picked up two tanks from my LDS yesterday-- 0 ppm carbon monoxide for each.

 

[DandyDon]

Picked up two tanks from my LDS yesterday-- 0 ppm carbon monoxide for each.

After several of those you'll start to wonder why you bothered, until you get your first reading...!

Don't stop testing.

 

[Prop Joe]

I have been thinking about posting from the PMs I received from the Coz operator, who gave me permission to post his PMs, but refuses to post openly. What's wrong there? I have decided to only summarize some points; make of it what you will...

He claims to also be an expert in industrial gas analysis, but does not claim to have ever tested a tank of scuba air on Coz...?

He does a lot of business with the primary fill station which supplies many operators on the island, but I do not know any other details about his business relations?
​

DD,
I know it is possible that a electrical compressor using dino/mineral oil as lubrication can make CO. All of what you are saying is possible. I commend you for testing. I'll probably get a CO tester after diving with your "friend" in March . From my limited exposure to the testing for CO, the calibration gas is the expense. But,
In this experts opinion the gas is safe? What is the limit at what depth? Smoker or non-smoker? Overweight, obese, dang theres a lot of veriables...
I would like 00.00 on all of my readings of my new CO tester. Is that possible?
I find it hard to believe a guy with experience in the "industrial gas analysis" would put himself or friends/family in harms way?

You got me thinking and I'll probably buy a CO tester, Not just for Cozumel though....​

 

[cruiser]

Picked up 4 tanks from my LDS today. One tank had 1 ppm CO, the other three had none.

 

[DandyDon]

DD,
I know it is possible that a electrical compressor using dino/mineral oil as lubrication can make CO. All of what you are saying is possible. I commend you for testing. I'll probably get a CO tester after diving with your "friend" in March .

Who dove with whom in March? I got some 5 ppm readings in Roatan in February. I'm confused here.

From my limited exposure to the testing for CO, the calibration gas is the expense.

Oh no, not really. You can get a pretty big bottle reasonably really.

But,
In this experts opinion the gas is safe? What is the limit at what depth? Smoker or non-smoker? Overweight, obese, dang theres a lot of veriables...

I was surprised at the arrogance I received from the local Op since no one there seems to be testing. Many Ops there depend on that fill station to keep themselves in business so none of them want to admit that there is a problem, and it is a respected station - but when new facts appear, damn! 10 is the maximum allowed in the US, 15 the highest max for any country developed enough to have a rule so diving those 17 tanks was a little unnerving - but I'd ruined the other tester so accepted that just maybe the one was off. IT WASN'T! Later testing showed it on the money! Another close call survived, but then I drive on hiways every week; life comes with accepted risks we try to manage within reason.

I would like 00.00 on all of my readings of my new CO tester. Is that possible?

Yeah, most of the testers do have that capability, but you can't take parts per million that seriously, and testing will always have a few points of accuracy leeway. Even tho the UK has 3 ppm for a max, I question that a field tester can be trusted to be that good. What we need to watch for are trends, and ultimately the over 15 reading - like if you get a 50 or more, confiscate the tank without diving! Probably ought to do the same with 17, but we're learning.

I find it hard to believe a guy with experience in the "industrial gas analysis" would put himself or friends/family in harms way?

I saw evidence that he got off of his high horse later and is probably taking some quiet actions, but we do have to be on guard ourselves obviously.

You got me thinking and I'll probably buy a CO tester, Not just for Cozumel though....

No not just for Coz at all; the risks are probably greater in many other destinations.. It's a wide spread issue long ignored by fillers and divers alike - all across the Caribbean & Latin American Area to be sure as well as around the world. But then automotive seat belts were considered frivolous when I got my first set install in the 60s; things can and do change at times. Thank gawd I was wearing them when I rolled a car a few years later.

ALL compressors need to have inline monitors that are competently maintained. We're a long ways from that to be sure, and it's going to take a lot to change this, but it's a serious need.

ALL serious Ops need to have two CO testers for spot checking tanks along with bottles of 10 or 20 ppm calgas for testing the testers. One is not enough since they do need to be sent off at times.

ALL serious divers need to be carrying field testers and checking tanks everywhere, since we cannot trust the above two needs - and this is the only way we can affect changes: Catch them in their mistakes!​

Someday I hope to see DAN and the agencies get serious on this, but they depend on each other and new scuba business so much - they're probably all afraid to be first.

 

[swamp diver]

DD,
I would like 00.00 on all of my readings of my new CO tester. Is that possible?

Yes the high-end portables such as the BW Tech Gas Alert Extreme or the RaeSystems ToxiRae 3 have a minimum detection limit and resolution of 1 ppm.

The key is to use a calibration gas down in the concentration range one is hoping to find contamination. Although one can purchase calibration gas at 5 ppm CO/balance air I have found that the 10 ppm CO functions the best not to mention it is a stock gas while the 5 ppm can be custom making it much more expensive.

Having checked hundreds of tanks over a 5 year period the vast majority do register 0 ppm. Usually if you find one in a batch with some CO you will find others from the same run but with differing concentrations which typically reflects the volume of hopefully clean residual air remaining in the tank prior to the contaminated fill.

In the tropics one does have to be careful not to leave any of these detectors in the direct sun as the extreme heat will increase the background reading by a few ppm. If you calibrate in the cool room with AC back home and then operate the unit at 35 C (95 F) with high humidity at the dive destination the monitor will likely show 1 or 2 ppm as background due to the change in environmental conditions. On the BW Tech unit one can autozero the unit if sure there is no CO in the environment and this will return the baseline to zero. On the ToxiRae 3 the temperature compensation circuit seems to be better and I have not found as much drift due to heat.

In the future though improved accuracy in the concentration range we are interested in will be possible by using a medical rather than an industrial CO sensor in these monitors. Hopefully if Analox sees there is a market for a portable unit in the dive industry they will design an new unit using a medical CO sensor which typically has a range of 0 to 100 ppm and are used to monitor breath CO concentrations in the low range.
http://www.citytech.com/PDF-Datasheets/mco.pdf

By the way synthetic not just dino/mineral oil can diesel and produce CO if the compressor is hot enough.