Breathing the gas from your BCD

[LI-er]

Here in our Egypt Red Sea liveaboard during a briefing we were told that the upcoming dive would be from zodiacs and we were to do a negative entry, all splashing at the same time so we don't end up on top of each other, and meet up below the boat.

Then he says to make sure you're negatively buoyant breathe all the gas out of your BCD.

It's always been my understanding that breathing this gas is extremely dangerous and I've read one account of someone dying a horrible death from a bacterial lung infection.

I questioned the advice and the DM had no clue what I was talking about.

 

[lexvil]

Think of it as sucking the air out.

 

[inquis]

I was taught to rinse the BC and would have no issue sucking the air out of mine. Rental gear may be a different story, but rinsing with a sterilizer (e.g., Steramine) could resolve that concern.

 

[johndiver999]

I've seen many people do it many different times- probably hundreds of times. When I do it, I try to pull air into mouth rather than suck into the lungs.

I use an air 2 now which prevents you doing this, so I don't do it anymore, but I honestly think it is not as dangerous as many people seem to think.

I also know someone who swears it (using the BC to inhale and exhale into) saved him in an emergency ascent. I don't doubt there is some danger in the practice.

 

[Divin'Papaw]

I've seen many people do it many different times- probably hundreds of times. When I do it, I try to pull air into mouth rather than suck into the lungs.

I suck the air out of my wing all the time. Most charters actually as I typically enter the water "hot" and begin my descent immediately. As you suggested, I do not suck the air into my lungs, or at least I try not to. I don't take super deep breaths. I rather fill my mouth, then blow the air out, and repeat this a few times until my wing is empty.

 

[uncfnp]

This has been a frequent discussion on SB as I am sure you know. To my knowledge there has been 1 documented case of infection from breathing from BCD over the history of scuba diving.

Taking a breath from the BCD for a good negative entry was something I was told diving WPB Florida many years ago and maybe a few times since. For the average diver it is totally unnecessary. Just give the BCD a good squeeze with the vent/valve open.

But would I do it in an emergency or truly needed for descent? On my own BCD absolutely. No worries. On a rental? Only for a true emergency.

 

[Eastwest]

As a last resort with myself being in a out of air situation , breathing off my buoyancy compensator instead of dying makes good sense to me . Been there done that Rumdumb

 

[coldwaterglutton]

A good reminder to rinse your bladder/wing with fresh clean water -- and dry it! -- after every dive. The drying though is the hard part. I usually use the residual tank pressure to blow it out until the tank gets to 300 psi or so.

 

[KatieMac]

Then he says to make sure you're negatively buoyant breathe all the gas out of your BCD.

...

I questioned the advice and the DM had no clue what I was talking about.

Guessing his first language wasn't english and you were taking him too literally

 

[Bento.Box]

I see no reason to do that and advise against it.
If you push the button and hold the hose up, the air will get out.