From: "John Nitrox" wrote:

> It's too bad that nothing stuck out from that day.

It was a very ordinary day.  When the symptoms started, as I was driving
back home, it was a bit like muscle fatigue in my right arm.  I recall
thinking it was a bit odd, but didn't worry much until late that night, when
the pain got progressively worse.  I took a ride in the chamber the next
morning.

> I'm thankful that your DCS
> experiences haven't left you unable to dive or limit your diving, and I
> hope there's no case of the bends in your future.

I got bent once since then, for reasons I understand all too well.  In the
middle of a series of liveaboard dives, 6 to 7 a day, the mate filled my
tank with air instead of 32%.  This time it was my left arm and it started
almost exactly like it had the previous time, which is the only reason I
knew I'd taken another hit.  I already knew why.  I noticed air and nitrox
tanks hooked to the whips at the same time and analyzed my tank to see what
was going on.  When it turned up closer to air than to 32%, I checked the
tank I'd just used.  It was closer to air too.  Had it been a normal dive
day, a couple modest dives with an hour or so surface interval, I'd probably
have escaped unharmed.  Having spent more than a day on the edge of ND
limits, it was enough to do the trick.  Like the previous time, a couple
hours later, the sensation started.  The previous time was no big deal, so
this one would be OK too, right?  Wrong.  That was several years ago and
I've still got occasional discomfort in my upper left arm, elbow and two
fingers of my left hand.  It's not a big deal, but it's annoying.

I've discussed this on this forum before.  On Strike's suggestion, I checked
with a hyperbaric specialist.  He indicated that I was way, way to late to
do myself any good.  As I've said before, if you're going to be stupid, it
helps to be tough.  I knew better than to breath a tank of nitrox I had not,
personally, tested and I had my analyzer with me.  In fact, I tested the
first couple of tanks from the membrane system and when they were OK.  Given
the hectic dive schedule, it was easier to let it go than to test every
tank.  Hindsight is 20-20.  I just didn't count on a mate that didn't have a
clue.  It later turned out that he wasn't even a certified diver, let alone
qualified to be filling nitrox.

Lee