You’re 100 feet down with two
buddies. Both come to you out of
air. What do you do?
If you’re as experienced and
alert as one diver we know of, you
could pass your primary second
stage to one buddy, give your
octopus to the second, then begin
a slow ascent valving fresh air into
your buoyancy compensator and
breathing through your BC’s oral
inflator mouthpiece. It’s a little
tricky and takes some practice,
but it works. Yet none of the
commercial training agencies
teaches BC breathing at any level.
In fact, since we first reported on
this technique several years back,
the industry seems to have closed
ranks against it, even though it’s
been successfully tested in a
variety of predicaments.
We’re hardly advocating
breathing BC air as a standard
practice — only as a last resort.
Even if you suck your tank dry, you
can get some air through your
regulator as you ascend and the air
in your tank expands. But once
your tank is bone dry, you’ll still
have residual air in your BC (or at
least in your inflator hose). If you
added air with your power inflator,
it will be pure and contain 21%
oxygen. If you orally inflated your
BC, it will still contain 16% oxygen.
Bear in mind that air in your
BC will also expand as you rise. If
you put your BC mouthpiece in
your mouth and keep trying to
inhale and exhale while you rise,
you should be able to do without
air for at least 20 seconds. By then,
air volume will have increased
enough to provide a breath.
Studies conducted by the late Al
Pierce of the YMCA concluded that
you can exhale back into your BC
and keep rebreathing the same air
13 times or more without becoming
overly hungry for fresh air. (After
all, exhaled air is good enough for
artificial respiration.) With this
technique, instead of free-ascending
with no air, you’ll have some air
as you rise, which will allow you to
make a slower and safer ascent.
Even so, agencies refuse to
teach this technique at any level.
The key objection voiced by SSI,
PADI, and even DAN seems to be
the possibility of respiratory
infection from bacteria inside the
BC. However, BCs used for training can be disinfected with
solutions readily available in dive
shops. Or you can use benzalkonium
chloride, which is available
at drug stores under the brand
name Zephiran chloride. Apparently
the Coast Guard uses
Listerine. Besides, why should you
be concerned about a lung
infection in an emergency? There
are a helluva lot more cures for
respiratory infections than there
are for drowning.
The second biggest objection
made by training agencies is
that divers will need to master
new skills and perhaps to overlearn
some old ones. For instance,
you must be able to clear
the ounce or so of water from your
inflator hose mouthpiece without
choking. Other skills required vary
depending on whether your first
stage is still supplying air. Additional
objections include difficulties
with buoyancy control, such as
ascending too fast or the possibility
of arriving on the surface with no
lift in the BC.
Frank Toal of NAUI summed
up the attitude of the certifying
agencies and manufacturers we
contacted by stating that BC
breathing “...could be used as a
last-ditch effort versus drowning,
but, because it is at best a very
difficult technique, it is not taught
in any course as required training.”
He also brought up the decadesold
bugaboo about the potential
for carbon dioxide poisoning if a
CO2 cartridge had ever been fired
to inflate the BC. Of course, if
you’re still diving with a BC that
old-fashioned, you’re probably
too stubborn to learn new skills
anyway.
The consensus seems to be
that keeping things simple
reduces the chance of panic.
Retired UCLA professor Glenn
Egstrom cites a phenomenon
called “peripheral narrowing,”
which is the tendency to lose
track of one’s options under
stress, thereby subverting the
reflexive nature of trained
responses. While that may be a
valid consideration, does it make
sense for those charged with the
safety of others (e.g., Rescue,
Divemaster, or Instructor levels)
to not even be exposed to this
proven technique for handling
out-of-air situations or equipment
malfunctions?
Dave Walls of PADI spelled
out his agency’s recommended
options for low/out of air situations,
in order of priority:
- Make a normal ascent, if your
tank isn’t completely empty;
- Ascend using an alternate air
source (redundant supply or
buddy’s octopus);
- Execute a controlled emergency
swimming ascent;
- Buddy-breathe with a single
regulator supplied by another
diver;
- Make a buoyant emergency ascent.
However, isn’t a controlled
emergency ascent or a buoyant
emergency ascent safer if you have
a few breaths of air from your BC?
Knowing you’ve got at least one
more ace up your sleeve might
help keep you cool as you weigh
your options. Hopefully, you’ll get
things under control before you
ever need to use your BC as an
alternate air source. But it’s there
if you need it.
— D. L.