14-12 Change A
U.S. Navy Diving ManualVolume 3
An improper valve line-up on the console. This can be verified by
checking oxygen percentage on console oxygen analyzer.
Accidental opening of the emergency gas supply (EGS) valve.
2. When the problem is corrected:
Ventilate each diver for 20 seconds and confirm divers are on decom-
Continue decompression as planned. Do not lengthen stop times to
compensate for the time spent correcting the problem.
CNS Oxygen Toxicity Symptoms (Nonconvulsive) at the 90-60 fsw Water Stops.
CNS oxygen toxicity symptoms are unlikely but possible while the diver is
breathing 50% helium 50% oxygen in the water at depths 60 fsw and deeper. If
symptoms of oxygen toxicity do appear, take the following actions:
1. Bring the divers up 10 feet and shift to air to reduce the partial pressure of oxy-
gen. Shift the console as the divers are traveling.
2. Ventilate both divers upon arrival at the shallower stop. Ventilate the stricken
3. Remain at the shallower stop until the missed time at the previous stop is made
4. Resume the planned decompression breathing air.
5. Upon arrival at the next shallower stop, return the divers to the 50% helium
50% oxygen mixture. Ignore any missed time on the 50/50 mixture. A recur-
rence of symptoms is highly unlikely because of the reduced oxygen partial
pressure at the shallower depth.
Red Diver has an oxygen toxicity symptom 5 minutes into his scheduled 9 minute
80 fsw stop. The stage with both divers travels to 70 fsw and the console is shifted
to air. Upon arrival at 70 fsw, Red diver is ventilated for 20 seconds followed by
Green diver. The divers remain at 70 fsw for the remaining 4 minutes left from
their 80 fsw stop and then start their 10 minute scheduled 70 fsw stop time at the
completion of the 4 minutes. Upon reaching 60 fsw, the console is shifted back to
their 50/50 mixture and both divers are ventilated.
Oxygen Convulsion at the 90-60 fsw Water Stop. If symptoms of oxygen toxicity
progress to an oxygen convulsion at 90-60 fsw despite the measures taken above, a
serious emergency has developed. Only general management guidelines can be