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George,

Thanks for writing the informative O2 toxicity post
to counter what others posted.  They are just parroting what they
have been taught and don't even realize that their source may be
wrong or incomplete.  Don't take it personally when they argue,
because I'll bet in a lot of cases the argumentative tone comes 
from the confusion of trying to figure out that maybe what they
were taught was wrong and they're trying to sort out the truth.

Unfortunately the same situation occurs all the time in life 
as well as in tech diving.

I'd like to hear more about O2 toxicity since the only info
I had before came from PADI and TDI.  Your post was my first
clue that the O2 clock stuff might be baloney.

Could we go over how you guys handle 02 toxicity issues again?
Starting at the beginning?

Don W.

Trey wrote:
> 
> I know what you mean . I need to get over worrying about it. I probably
> would have let these guys stew in their own stupidity had one of them
> not made it personal.
> 
> armantrout@at*.ne* wrote:
> >
> > I just don't have the motivation to correct the people
> > who already "know it all", and everybody else just comes
> > to us to find out the real story anyway.  So what's the
> > use?
> >
> > > Totally and completely untrue - Martin you need to knock it of. You are
> > > not even remotely close to being right about any of this - not even
> > > close. You are one serious idiot for getting on here wiht thin sdegeree
> > > of misinformation.
> > >
> > > Can some of the other WKPP guys who know what they ar talking about take
> > > over on this one - there are too many idiots spouting on this list right
> > > now for me to field enverything - need some help here.
> > >
> > > Martin M. Quigley wrote:
> > > >
> > > > Scott -
> > > >         The "oxygen clock" is a useful concept to think about the body's
> > > > accumulation of oxygen toxicity over time. There are two principal type
of
> > > > oxygen toxicity - pulmonary and CNS. Pulmonary oxygen toxicity starts to
> > > > occur with long-term breathing (over 24 hours) of oxygen at a partial
> > > > pressure over 0.5. The higher the partial pressure of oxygen, the
shorter
> > > > exposure time required before pulmonary oxygen toxicity begins to
develop.
> > > > Pragmatically, a recreational "technical" diver generally doesn't have
to
> > > > worry about pulmonary oxygen toxicity unless he/she needs to undergo
> > > > extensive recompression therapy (more than a Navy Table VI).
> > > >         CNS toxicity is more critical. The higher the partial pressure,
the
> > > > "faster" the oxygen toxicity clock runs. Exercise, carbon dioxide
retention,
> > > > and other factors increase the susceptibility to CNS oxygen toxicity.
The
> > > > NOAA limits I cited are "conservative" limits, based on some "wet"
diving
> > > > human experimentation plus industry experience. In addition to the
limits I
> > > > included (which are single dive limits), there are also 24-hour limits
for
> > > > repetitive dives. Staying within these limits exposure a diver to a
very low
> > > > risk of CNS oxygen toxicity. Exceeding a partial pressure of 1.6, even
for a
> > > > few minutes, exposures a "working" diver to a very high risk of an
oxygen
> > > > seizure.
> > > >         My specific example (125 minute exposure to a ppO2 max of
1.4)is just
> > > an
> > > > example of the use of the tables. If you're going to be exposed to O2
over
> > > > 0.5 partial pressure on a dive for 125 minutes, you should limit the
maximum
> > > > ppO2 at any point of the dive to 1.4.
> > > >                 Martin
> > > >
> > > > > -----Original Message-----
> > > > > From: ScottBonis@ao*.co* [mailto:ScottBonis@ao*.co*]
> > > > > Sent: Tuesday, February 08, 2000 6:42 PM
> > > > > To: quiglem@ib*.ne*
> > > > > Cc: techdiver@aquanaut.com
> > > > > Subject: Oxygen Limits
> > > > >
> > > > >
> > > > > Hi Martin,
> > > > >
> > > > > On 2/7/00 you wrote;
> > > > > << ... The 3rd Edition of the NOAA Manual (4th due out this
month
> > > > > - but I don't expect changes) has time/pO2 limit tables for
> > > > > oxygen exposure for working divers as follows:
> > > > > SINGLE EXPOSURE Maximums:
> > > > >    PPO2 ATA     Minutes
> > > > >       1.6           45
> > > > >       1.5          120
> > > > >       1.4          150
> > > > >       1.3          180
> > > > >       1.2          210
> > > > > (i.e., if your underwater time is planned for 125 minutes, the
> > > > > max. you can breath at any point in the dive is 1.4).... >>
> > > > >
> > > > > Could you please explain a little more about the parenthetical
> > > > > statement.  How does this correlate with the concept of an "Oxygen
clock?"
> > > > >
> > > > > Thanks a lot for your help.
> > > > >
> > > > > Scott
> > > > >
> > > > >
> > > >
> > > > --
> > > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> > > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
> > >
> > > --
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> > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
> 
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