Children die playing with scuba gear left in pool - Jensen Beach, Florida

[Wookie]

I have not seen a report on what the helium content of the tank was, nor who supplied the tank. I have a hunch that the husband of the "woman who lived at home" filled the tank with close to 100% helium but failed to mark it and was away at the time. But I am guessing.

Your guess is not correct. It was 100%, the owner was present.

 

[Ayisha]

Your guess is not correct. It was 100%, the owner was present.

How did it happen?

You said it wasn't marked as helium. Did the owner put it aside without markings at some point, and then got it mixed up with a tank that was expected to contain a life-sustaining gas? It wasn't analyzed or labelled, and regs went onto it?

 

[Kay Dee]

The kids, Zale Dudas, 9, and her brother Saxon Nairne, 7, were with their father Rodney Nairne. Rodney Nairne and Suzie Dudas own Submerge Scooters
Two young siblings die after possible drowning incident in Jensen Beach
and https://weartv.com/news/local/2-young-siblings-die-after-using-scuba-equipment-in-florida-pool

Well that certainly hits home. Tragic enough as 'nameless children' but having personally known one of the parents it's a gut punch.

My sincere condolonces to the family and friends of those directly concerned. Having two (now grown) children of my own I can still only barely imagine the heartbreak, and the circumstance. At a loss for words.

 

[beester]

If all you dive is air, then having them unlabeled is common, and very little risk. If you have tanks with various other mixes around, then labeling all of them is a good idea, especially if some of them might contain trimix.

The only unlabeled tanks I dive are the ones I use at the aquarium. They are all filled by an on-site compressor, so air is the only option. No banks of He, O2, Ar, or anything else available.

The only time my tanks are unlabeled is when I take them in to get filled, and that only lasts until I pick them up and analyze them.

I still analyse tanks and label them or check if the analysis matches the label before I put the tanks in the car for a dive AND before I put the reg on it. As should we all, so the labeling of tanks in storage is from a safety point of view not so necessary IMO... yes it is easy for sorting various tanks and "fills" ;-)

 

[beester]

CAGE is AGE in a specific location.

I rent my helium in big T-bottles. It is very expensive. So is the daily tank rental. When I have finished a dive trip and have helium left over, I will fill a regular tank with it so I am not paying rent until the next trip. I will, of course, label it when I do, since I will be using it for mixing when I am preparing for the next trip. I have a booster that makes this possible. I would guess that it is an unusual circumstance--there can't be many people in that position.

A mix of 10/50 or 10/70 is normally only used for diving when you are getting down to the 90m/300 foot range. That is a seriously hypoxic mix.

I would do the same in the past (circumstances changed with a rebreather now). I was thinking abit about the mix. For sure a pure He filled tank is very dangerous, breathing pure He will have you black out in a couple of breaths (trust me I've tried). But hypoxic mixes indeed would need to be VERY hypoxic to cause this incredibly sad accident. Even a mix with only 15% helium would be no big problem at 2 m (6ft) it's already no longer hypoxic, and even breathing a 15% for prolonged times on the surface is not going to cause real issues as long as your activity level is not super high.

Anyway as a dad of a little son, I just can't imagine the heartbreak this family has to go through now!

 

[Kay Dee]

Now that I have at least digested the shock of knowing who it was, if not quite accepted said fact, some words return.

Earlier in the thread someone posted a comment about the purported difficulty of resuscitating someone who has breathed pure helium (and asked / hoped) that one of the medicos might step in and answer that question). However that post now seems to have been deleted or I cant find it, having just scanned through the whole thread.

This 'story / word of mouth truth' passed around back in the day - by some of the big 'names' in tech diving instructing back then - with the reason given being that, besides having no oxygen to sustain life, the pure helium did something to the lungs that made it hard if not impossible for the uptake of oxygen post incidence to happen quick enough to save / revive said person. Although I had no intent of breathing pure helium, I believed it at the time, given whom was saying it.

However, many years later I personally knew someone who breathed pure helium off a surface supplied deco bar station (yes, a crew member, who had done the empty O2 to full O2 bottle switch many times before accidentally / inadvertently switched from the banks of O2, to a helium bottle.) Long story short, the diver passed out, luckily floated to the surface, and again luckily, was seen by someone on the back deck, who dived in and dragged him into the 'elevator lift' and got him back on deck. Once revived, it was as if nothing much had happened, save for him using up one of his nine lives, of which he had already used a few.

So yes, it would be very advantageous now to all interested parties, given that we seem to now know with a very high degree of probability / certainty, that it was pure helium breathed by the children, if some medicos knowledgeable in that field would step in and clarify the issue / possible complications from breathing pure helium.

 

[Storker]

Trimix separates (not unlike salad dressing) due to helium being significantly less dense than oxygen and nitrogen.

This goes against what physics says. If fluids (gases or liquids) are miscible, they will mix. Only question is how fast. And when they are mixed, they stay mixed.

In the case of the salad dressing used as an illustration, the liquids aren't miscible, so they separate according to density.

 

[Julius SCHMIDT]

Diving royalty, the names Zale Parry and John and Evie Dudas, grandmother, Suzie Dudas mother.

The pure horror

 

[mderrick]

The reason for 'rolling' tank after blending trimix using partial pressure method is that, depending on exactly the flow rates and timing, the helium and nitrox can layer or create "bubbles" of not fully mixed gas that will result in unstable/inaccurate analysis if it's done immediately after blending. The cause is temperature differences in the gases as a result of the methodology used to introduce the gases in to the cylinders. If even a modest amount of time passes between blending and analysis, the gases will fully mix automatically due to Brownian motion once the temperature is near uniform. Once the gases mix, they will stay permanently and completely mixed due to that same Brownian motion. I did extensive research and testing of these gas physics issues prior to banking the various trimix blends at Fill Express.

As mentioned previously, hobbyist blenders do indeed sometimes 'stash' unused pure helium in spare scuba cylinders rather than pay bottle rental fees. Proper labeling is critical, but in my experience labelling alone is not sufficient because others may not understand the meaning of a contents label alone. How many sport divers would understand a label "He 100" or even a label "Tx 10/50"? I am a gas blending instructor and I teach my students to also segregate and chain or otherwise secure any cylinder containing anything other than sport diving gases (It is also an OSHA safety regulation as well.) There are gas handling standards that mandate incompatible valves for different classes of gases, such as CGA-540 for oxygen and CGA-580 for inert gases such as helium. This accident is a strong argument against the practice of ever storing pure helium in cylinders with SCUBA valves.

That the victims were breathing almost pure helium (as now revealed in a previous post) rather than a diving gas containing 10% oxygen makes much more sense to me than the original speculation the gas was 10/50 or 10/70. Although a PO2 of 0.11 is not enough to sustain consciousness in many individuals, LOC is not as rapid as might be expected; in part due to CO2 also being exhaled and in water which will might trigger mammalian diving reflex. Breathing almost pure helium is a very different circumstance, and LOC would be quite rapid (there are documented cases of LOC with just a few breaths of helium from party balloons).

 

[clownfishsydney]

Wow, this is awful news. I assume that Rodney Nairne is an Australian, seems that he probably is based on the fact that I used to know a Rodney Nairne in Sydney who built his own rebreathers in the early 1990s. He is certainly an extremely experienced diver who you would think would know the dangers of having a pure Helium cylinder lying around. My thoughts are with him and his family.

Just confirmed with a friend that Rodney is an Australian. He was back here visiting his parents a month or so ago. As you could imagine my friend is devastated, he was close to Rodney, both built their own rebreathers and dived together.