Anywhere thawed out yet?

[matt t.]

Any perceived decompression benefit of using a higher ppo2 at 30
feet with 80/20  is then given back  by the lowered ppo2 at 20 feet, not
to mention the fact that the presence of the inert gas in the  breathing
mixture defeats the purpose of using  oxygen in the first place ( see
the Physiology and  Medicine of Diving) .   The ppo2 of 80/20 at 20 feet
is 1.28, not much of an oxygen window, and at 10 feet it is 1.04 -
useless for deco. To make matters worse, you can not get  out from your
30 foot stop in an emergency ( not doing the other stops)  on  the 80/20
mix without really risking a type 2 hit. (G.I. III)