2 Examples of Why You Should Always Anaylse Your Gas

[GLOC]

These 2 have been lifted from DIRx as they provide salient examples of why people should analyse their gas and mark their bottles accordingly before diving, even if they have filled the bottles themselves. Both examples make sobering reading.

This first one is taken from a report by AG following a course he did with Richard L in Croatia in 2002 where someone had an ox-tox incident.

On this list, in our GUE classes, and within our projects we have
consistently reiterated that divers must carefully identify the true risk
of a given dive. With gas diving, oxygen toxicity remains the most
consistent and yet often under appreciated risk. Irresponsible mixing,
convoluted marking/procedures, and careless divers are almost exclusively
the culprit in these cases. The following actual account depicts an all too
common over confidence that nearly cost one diver their life. I encourage
everyone to read this report and to appreciate the risk to which divers
expose themselves and their team.

While conducting a Tech 1 in Croatia this last week we were faced with the
following incident, one that should prove educational to all. It is for
this reason that we wanted to bring it public attention. The course was
conducted in Croatia, on an Island called Pag. The initial part of the
training, DIR fundamentals and critical skills went well, with students
undergoing training with myself and Richard Lundgren. After two days of
fundamentals and 4 days of critical skills training, we were ready to move
forward to the experience portion of the class. During this portion, the
students plan and execute two dives to a max depth of 36 m, on a 30/30
triox mix and decompress on Nitrox 50.

The logistics of the course were coordinated by the local dive facility.
The owner of the facility was involved with the class. Upon returning from
the sixth day of training, Diver X who also is the facility owner, began
the nightly filling process for the next day of diving. Oddly enough in
Croatia, the same valve fitting (threads) is used for all gases,
facilitating confusion for those that are not properly vigilant. In fact,
diver X confused the supply bottles, accidentally filling oxygen instead of
Helium into his own back tanks. Failing to heed the directions of his
instructors to properly analyze his gasses, diver X marked all his
cylinders as analyzed while, in fact, his back tanks were never analyzed.
Clearly such a mistake placed the diver and his team at tremendous risk; in
this instance it almost cost him his life. Individuals must bear in mind
that these actions do not occur in a vacuum, and that rescuers and other
team members are compromised when they must take extreme actions to
safeguard the safety of other members.

Following the execution of all pre-dive drills (conducted in seven minutes)
both groups proceeded with their dive. Nineteen minutes into the dive,
Diver X gently flashed me with his light to get my attention. He pulled his
regulator out of his mouth (as if he was giving me an OOA) but instead
began to convulse at 36m. I immediately donated my regulator, grabbed his
harness (with my left hand) and tried to put a regulator in his mouth. His
convulsions were very strong and I could not initially get the regulator in
his mouth. I proceeded to swim him closer to the wall to avoid being swept
away by the current. Diver X convulsed for a solid two minutes. We then
started up, my right arm under his right arm, holding him firmly while
keeping the regulator in his mouth. During this process I tried to remain
conscious of maintaining an open airway.

We then proceed up, with the help of my assistant, controlling all buoyancy
with my left hand. It took about one minute to reach 17m; there Diver X
began to convulse again. Following this convulsion I slowly led him to the
surface. Upon surfacing, I called for the surface support boat, which
initiated an emergency response. I removed my mask and his and prepared to
start mouth-to-mouth breathing. Fortunately he was breathing, making this
unnecessary. We then removed his gear and put him on the Zodiac.
Upon establishing that all divers were safely at the surface with no need
for additional decompression, we decided to start back to the dock, where
we could meet the ambulance. During the ride to shore, Diver X began to
come around, his color improved and his breathing became more rhythmic. We
administered oxygen during the return trip to the dock and by the time we
had arrived, he was feeling and looking much better. Upon reaching the dock
the ambulance took over, taking him to the hospital for further testing.
Further testing proved that there was no lung damage or bends and only as a
precaution did they treat him for near drowning.

Subsequent analysis proved that Diver X's cylinders had been improperly
marked. At this point we re-analyzed all diving cylinders, demonstrating
that the only improper marking had been on Diver X's cylinders. It turns
out that although his tanks were marked for 30/30 he was, in fact,
breathing 50.1%.

Although this event ended well it was clearly filled with dangerous
potential. All divers should use this as yet another example of the
importance in following careful procedures for gas analyzation and tank
marking. This must be the case whether they fill themselves or whether
others fill the tanks for them. In this particular case Diver X allowed his
personal filling of the tanks and the accuracy of the other mixes to induce
a false sense of confidence. The diver later told me that he is keenly
aware of his error, embarrassed by his arrogance and grateful to be alive.
It is my hope that this account will help others realize that short cuts
often fail and seemingly impossible things can and do occur. Ignoring the
proper procedures can cause an accident very quickly.

Andrew Georgitsis
GUE Training Director

The next one was posted by a US GUE Instructor and shows why you should test a new set of tanks (to you) which have gas in them.

And for a second lesson in why you should always analyze your tanks :

Two friends and past DIR-F students diving locally shortly after the incident in AG's course.

Diver 1 had just purchased a set of used double PST 130 tanks as his first set of double tanks. The tanks had approx. 1200 psi in them. Rather then dump the tanks and refill the decision was made to dive them in order to check buoyancy with a minimum reserve. Both were recreational divers and they assumed the tanks were filled with air or Nitrox 32. Plans were made for a skills dive with a max depth of 30 feet.

Divers descended into 20-25 feet of water, Diver 1 took a few breaths off the tanks and then passed out. Diver 2 performed an unconscious diver recovery, on the surface breathed a couple of breaths into him and Diver 1 began breathing and regained consciousness.

They swam into shore and then analyzed the contents of the tanks - pure helium.

Later we tracked down the history of the tanks. Diver 3 had borrowed the tanks from Diver 4 who originally owned them. Diver 3 had dumped the tanks, filled them with He and let them sit unmarked, planning on topping with nitrox 32 in the near future. Plans changed, a period of time went by and Diver 3 returned the tanks to Diver 4 still unmarked. The tanks sat until Diver 4 changed jobs and was leaving the area. At this time he advertised the tanks for sale and Diver 1 bought them.

So

1. Label the tanks properly at the time of filling
2. Analyze the contents of tanks personally prior to the dive.

Marc Hall

Lessons Learned:

Always analyse your gas before you get in. I know that Marc above said 'personally', but if you have a big exped/course with lots of bottles and time is of an essence, then there must be at least one independent checker of the fills to ensure that the filler hasn't made the mistake like the first example.

Don't become complacent, especially if diving in a group or team. One day you might be breathing their gas and you will want them to have the correct gas otherwise you might have 2 casualties instead of one.

Safe diving.

[Bantam]

Good Post. Just a thought (which I'm just double checking my brain's working today) - analysing the second tank would show 0% O2, right?

(Much like when I did the balloon gas tank which also showed 0%)

[GLOC]

Originally Posted by Bantam

Good Post. Just a thought (which I'm just double checking my brain's working today) - analysing the second tank would show 0% O2, right?

(Much like when I did the balloon gas tank which also showed 0%)

Yep, I would have also thought doing a proper reg check (ie breathing the regs to make sure the valves are turned on properly) on the surface would have showed up this issue because his Diver 1 voice would have gone rather high

[milldog]

G

could i ask were these premarked up cylinders or were they marked after the fill?

Graham

[Clare Gledhill]

All analysis labels should be filled in after filling and prior to the dive - but for clarity we don't permanently mark back gas cylinders.

Stage cylinder MOD markings are for in water ID purposes - there should still be an analysis label on them correctly dated, initialled and completed with gas percentages.

HTH

[GLOC]

Originally Posted by milldog

G

could i ask were these premarked up cylinders or were they marked after the fill?

Graham

Don't know as I wasn't there but does Clare's reply answer your question?

[milldog]

Originally Posted by GLOC

Don't know as I wasn't there but does Clare's reply answer your question?

No, (thanks for the sucking eggs info) yes i know thats what supposed to happen but i have seen this more and more,

when you drop cylinders off you should tape the fill you need to the cylinder however if they are wet this label can fall off and be reattached to one of your cylinders but not the one that you put it on, they get filled and now you have a case of the MOD21 has 100% or what ever and the OXYGEN has 50%, (Example)

Back comes diver picks up cylinders and doesn't test them because the tag he stuck on them were correct for the cylinders and away they go they obviously did pay any attention to the fill tape if there was one placed on it, bingo here we have the problems described. I carry an Anolox tester but how many don't! Its easy to get to the till and them say 1x 100% and 1x 50% cost is....... strengthens the idea that you have the correct fills, i once watched some "DIVERS" test a trimix by sucking on the reg and say yeah thats OK!!

EDIT: i dropped of my back gas for a 15/55 fill and ended up with a 55/15 fill???

good points though and strengthens the idea to test the mix I was just curious to the history of the incident

Graham

[GLOC]

Sorry about the egg sucking but all I had was the post which was put up on OD from the Quest list and I didn't understand if what you were asking was what Clare answered.

To me anyone who doesn't test the contents when they pick the cylinders up is somewhat daft. In addition, all the places I have been to, you have to write the cylinder numbers down on the check sheet from the filler and sign the analysis before you can take the cylinders away. Obviously this won't be a player if you do your own fills.

I have also heard about people testing He content by the sound of their voice or the sound it makes when the gas leaves the valve, but the person I know about checks the O2 content (which is the bit most likely to kill you) with a sensor and marks up accordingly.

Regarding your 55/15 fill, I hope you gave them sh*t and asked for a refill?

Regards

[milldog]

Originally Posted by GLOC

Sorry about the egg sucking but all I had was the post which was put up on OD from the Quest list and I didn't understand if what you were asking was what Clare answered.

not aimed at you mate,

Originally Posted by GLOC

To me anyone who doesn't test the contents when they pick the cylinders up is somewhat daft. In addition, all the places I have been to, you have to write the cylinder numbers down on the check sheet from the filler and sign the analysis before you can take the cylinders away. Obviously this won't be a player if you do your own fills.

I have never signed a book for the fill except on the nitrox course but that was part of the written work, other than that i have never signed a book, but due to some dodgy fills i have now test all mine, and i would recommend it to every one

Originally Posted by GLOC

I have also heard about people testing He content by the sound of their voice or the sound it makes when the gas leaves the valve, but the person I know about checks the O2 content (which is the bit most likely to kill you) with a sensor and marks up accordingly.

Yep i have seen this done as well, however a hard swim on the surface to the line breathing 15/55 will screw you over, all i can say is they must be better than my analyser, O2 should be checked because of the reasons i mentioned i was trying to understand how he got such a different fill

Originally Posted by GLOC

Regarding your 55/15 fill, I hope you gave them sh*t and asked for a refill?

Regards

Yep they paid for a local company JR services to sort it out for me

Graham

[GLOC]

Originally Posted by milldog

I have never signed a book for the fill except on the nitrox course but that was part of the written work

Okay, I have only got fills at Aquanauts, Vobster, NDAC and my LDS and they all use a book (for their paperwork AIUI)

Originally Posted by milldog

Yep they paid for a local company JR services to sort it out for me

Good, can't understand how they 'checked' the fill and got 40% out, that is worrying.