Hydrogen Sulfide (H2S)

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Iguana Don

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rainreg,

I just keep coming up with em.

When I was in the oil busisness I went through then "Oklahoma Blowout Prevention School" at the University of Oklahoma. In this class they taught us that H2S is absorbed into the drill pipe & other down hole equipment. Why then can we dive into caves, caverns, sinkholes etc. having layers of this to swim through. Why does this not effect the tanks & regs, not to mention your skin & lungs.

H2S is deadly stuff.
 
As far as hydrogen sulfide is concerned, it is not soluble in metal and will not pass into the diver’s breathing equipment. I believe that they probably meant, in school, was that the gas was absorbed into the drilling mud, etc. but not actually into the pipes.

Hydrogen sulfide is generally not found in phreatic (underwater) caves, but it is common in hydrothermal springs such as one might find in Yellowstone National Park. Divers would not be in these - - at least so far! Fortunately this gas is not absorbed through the skin so, unless it entered into the breathing apparatus, the diver would not breathe it – assuming it was in cave water in the first place.

I would wager that this would not actually be a problem for cave divers.
 
Dr.Deco,
To confirm what I stated, I called the School & spoke with one of the instructors, he advised me it causes a chemical reaction with the drill pipe & causes the pipe to become brittle. When the drill pipe comes out of the hole it is black & has to be tested before going back in.
Also there are several articles in the "Tech" magazines where they dive through this layer of H2S "Immersed". This is what prompted my question.
If it has this effect on steel drill pipe what then the effect on an aluminum cylinder & the rubber hoses?
More can be found on this at- http://www.api.org

[Edited by don on 10-03-2000 at 07:46 AM]
 
don:
[sp]I read your last post and see that your question involves materials science more than medicine and physiology. I can not actually comment on the reactions of H2S with the diver's breathing apparatus, other than that they probably can occur.
[sp]I would suspect that what happens in the drill hole (under conditions of increased H2S pressure and elevated temperatures)is considerably more severe than what would occur in a diving situation. Hopefully others can add something to this topic.

Michael Powell (aka "Dr. Deco")
 
Dr. Deco,
Thanks for your effort. Doesn't sound like a wise thing to do anyway.
 
Hi Don having done the same kind of courses you mentioned I also wondered about H2S and diving. As far as I’m aware H2S will eat into most metals except stainless steel and other specially treated compositions. But like Doc was saying this is usually due to high pressure/temperatures If you remember the escape apparatus is all pretty much the same as standard scuba gear (steel tanks, regs, rubber FFM) and that’s good for 100% H2S environment at surface so I would guess that you would have to be diving in some pretty gas cut liquid to achieve the same exposure.
 
Hi guys,
With regard to hydrogen sulfide and cave diving- here's the scoop. Hydrogen Sulfide, when present (not always the case) forms a "layer" in the water that is visible (much like a halocline). Typically when we (cave divers) encounter them, we simply move through the layer as expeditiously as possible, as it is absorbed through the skin. Wearing a drysuit, your skin exposure is fairly minimal, especially since the layers are usually only a few feet thick. You can also taste it as you are passing through ( a NASTY metallic sort of thing). As for the equipment, it does eat the chrome plating off manifolds, and regs. I am not sure about it's effects on hoses, etc, but I am sure it isn't great for them. We have a little joke about hydrogen sulfide layers in the cave community, as they frequently are found with haloclines in places like Mexico- it goes like this: Well, you do the nice saltwater intrusion tunnel in XYZ cave, then you get a nice acid bath for the gear in the hydrogen sulfide layer, followed by a freshwater rinse on the ascent!

Seriously, I hope this helped to answer some of your questions.

Chickdiver- OW Instructor, Cave Instructor, Mixed Gas Instructor
 
as it is absorbed through the skin...

It is? But Doc Deco said...

Fortunately this gas is not absorbed through the skin

Thats in line with what I was taught in HazWoper training too,and my H2S cert.

H2S smells like rotten eggs for the very short time you can smell it, or at least so I have been told. Metallic taste? Really?

TwoBit
 
Sorry, my bad- I have always been told that it was absorbed through the skin- however, I am not a doc. scientist, or other who would actually **KNOW** this for a fact. As for the taste, yes I do know that for a fact. I dove a limerock pit N. of Tampa about 2 months ago, descending through the layer there was a distinctive metallic taste to the inside of the mouth, not around the mouthpeice, as you would expect, but more n the insides of the cheeks. Once through the layer it stopped, same effect on the ascent. BTW_ define "short time" as in smell of rotten eggs for a "short time"- I smelled it on my hands for 2 days :(
 
H2S gas destroys the olfactory nerve endings quickly. A person will be able to smell it for a short period then the smell will go away. This is not because the gas is gone, but because the nerve endings are gone. Unconsciousness comes fairly quickly afterwards.

TwoBit
 
https://www.shearwater.com/products/perdix-ai/

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