American tourist dies while diving Cozumel caves.....

[DandyDon]

Yeah, I saw some guys dive Nitrox to 100 feet thinking it was air. I started testing my tanks for both the next day.

 

[Texas Torpedo]

I just got confirmation that the fills were being done by Meridiano and were EANx.
I will point out that nobody else got hurt, including open water divers using EANx who were going much deeper, and should have been affected.
They are going over everything in great detail and I'm sure they will find out exactly what happened.
One would think that the in-line CO Alarms would have sounded but there are other possible points of failure (IMO), especially doing partial pressure fills..
As many fills as Meridiano does, I don't understand why they don't bank at least 32%..

 

[DandyDon]

I just got confirmation that the fills were being done by Meridiano and were EANx.
I will point out that nobody else got hurt, including open water divers using EANx who were going much deeper, and should have been affected.
They are going over everything in great detail and I'm sure they will find out exactly what happened.
One would think that the in-line CO Alarms would have sounded but there are other possible points of failure (IMO), especially doing partial pressure fills..
As many fills as Meridiano does, I don't understand why they don't bank at least 32%..

Damn! I often preface my remarks about inline monitors with " We hope that they are maintained and operated correctly, but I'll test my tanks anyway." You have seen their monitors. Do you know how close they are to the operator stations so they can be easily heard?

 

[Texas Torpedo]

Damn! I often preface my remarks about inline monitors with " We hope that they are maintained and operated correctly, but I'll test my tanks anyway." You have seen their monitors. Do you know how close they are to the operator stations so they can be easily heard?

I don't know how loud they are when they alert but the one I glanced at in the EANx fill area was pretty close to the whips and I'd hazard a guess that if they alerted they would have heard it.
I got the impression with the people I've now talked to about this that they did not alert or record a dangerous elevation of CO.
One could speculate at the reasons for this..
- The gas was not contaminated
- The monitor was not properly calibrated
- The monitor's regulator was not set to flow properly and thus the gas was not reaching the actual sensor in the amount required to gain an accurate reading

 

[swamp diver]

First off we still don't know how it was determined that this diver died from CO poisoning and until it is reported that his tank had XXX ppm of CO as measured with hand held monitor the antecedent cause of death could be still speculation. As stated previously I do not believe that it is possible to get a blood COHb on the island so again any conclusions solely based on autopsy would be speculative.

I am disappointed to hear that this incident may have involved Meridiano as they have been proactive and did install four Analox CO Clear monitors, but when I looked at these a few months ago I saw problems, at least with how they were installed at that time. From what I could determine the monitors were isolated in the compressor room well away from where the operators filled the tanks and it would be doubtful if they could hear the alarms if the window and doors were closed between the compressor room and fill whips out on the floor.

There are numerous other potential points of failure one can think of such that a contaminated batch of air was not identified:

1. operators don't hear alarms
2. operators ignore alarms just as people ignore smoke alarms. The low alarm is set at 3 ppm so if there is constantly a low amount of CO in the compressed air say at 3 to 5 ppm the alarm may have become annoying and the units were shut down.
3. alarm thresholds altered from factory 3 ppm and 10 ppm
4. units not calibrated every 6 months as required
5. flow to units disconnected or units not powered as I saw recently here in Ontario
6. sensor no longer functioning


This just emphasizes that even with CO monitoring on the compressor things can go wrong such that contamination is not identified. Compressor CO monitoring is one part in several layers of defense against breathing CO contaminated gas, however the final defence remains the responsibility of the diver to check their own breathing gas personally with a hand held monitor that has been recently calibrated and known to be in good working order.

I'm still confused as to how Meridiano, if they are in fact the compressor station involved in this incident, could fill a tank with contaminated air ( or top off a nitrox tank when pp blending) since there are four (4) monitors on their system. Here is a photo of a pair of these monitors in action, but within the compressor room and not out on the floor where they should be.

 

[swamp diver]

Remember there are many factors operating here which could lead to one tank having much higher CO concentration than the others.

Merdiano does not bank their air as far as I know therefore the final CO concentration in the tanks would depend on the amount of presumably contaminant free air from the previous fill. A tank with only 500 psi vs. another with 1500 psi remaining will have very different final CO concentration if both filled with contaminated air at the same CO concentration. The diver who receives the tank which only had 500 psi in it prior to filling may be injured while the other is not if used at the same depth, same level of exertion, and assuming they are approximately the same age, free of heart disease, and non-smokers.

When compressors, more often than not electric, produce CO by burning their lubrication oil it happens quite quickly as the final stage discharge temp exceeds the autoignition point of the oil. Once the pyrolysis happens the entire load of CO could end up in only one or two tanks. If the compressor was unloaded or allowed to cool down again CO production will cease until it heats up under load again.

One is going to find tanks with all ranges of CO concentrations from zero to potentially lethal depending on when the combustion event occurred and the amount of existing clean air in the tank before the contaminated air was introduced.

 

[Texas Torpedo]

I am disappointed to hear that this incident may have involved Meridiano as they have been proactive and did install four Analox CO Clear monitors, but when I looked at these a few months ago I saw problems, at least with how they were installed at that time. From what I could determine the monitors were isolated in the compressor room well away from where the operators filled the tanks and it would be doubtful if they could hear the alarms if the window and doors were closed between the compressor room and fill whips out on the floor.

I'm still confused as to how Meridiano, if they are in fact the compressor station involved in this incident, could fill a tank with contaminated air ( or top off a nitrox tank when pp blending) since there are four (4) monitors on their system. Here is a photo of a pair of these monitors in action, but within the compressor room and not out on the floor where they should be.

View attachment 106019 View attachment 106020

I can verify that at least one was moved out to the EANx fill area, and possibly two, as of last week.

 

[swamp diver]

I can verify that at least one was moved out to the EANx fill area, and possibly two, as of last week.

Yes moved but were they calibrated, had air flowing to them at 1 lpm, and powered up?

I was in a shop up here several weeks ago where there was a nice Analox CO Clear on the wall which was unplugged and had no pressure line to the sensor. Teenage tank jockey had no clue as to why it was not hooked up.

 

[DandyDon]

Ok,inline CO monitors are great for the compressor operator, but not for the diver. Each diver needs to test his own tank.

 

[scubafanatic]

A few years ago I did a week of cavern/cave diving in Akumal and our instructor/trip leader told me one reason he used Aquatech/Villas DeRosa was because they used ELECTRIC powered compressors to reduce the chance of this sort of event happening.