Incident Report

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Incident Report 2020-05-01T16:26:00+00:00

O2 near hits

Incident Date


Incident Description

Pwll-y-Cwm (Wales) The diver was going for an extended dive on a homemade rebreather encouraged by its performance on an earlier dive that weekend. Egged on by a large audience (including other divers) the victim kitted up with some difficulty. Overweighted the diver plumitted to the bottom with a ppO2 of 2.4 (off scale) - the diver felt very unwell with a tingling sensation progressing up the body. Unwisely the diver stayed on the loop injecting diluent and trying to breathe down the ppO2. Surface was regained with some difficulty the diver having to haul himself up the line. Maddison Blue Springs (FL) Three divers were undertaking a tourist trip. Decompression was to be done on O2 but due to the popularity of the site and configuration of the cave the O2 was dropped inside the cave at 12 m. On the return two of the divers (including the wisened above) collected their cylinders and ascended to 6 m to switch to O2). The third diver switched to O2 immediately and reported all of the symptoms described above on her ascent. Eagles Nest (FL) The diver was conducting his first trimix dive using metric tables cut specially by his American dive partners. The diver returned to the entrance shaft ahead of the rest of the party at -55 m switched immediately from trimix to ahot nitrox mix. No illness was encountered in this instance.

Lessons Learned

0. Watch your ppO2 whether on open or closed circuit. 1. It is conjectured that whilst divers may be able to tolerate high ppO2 for a period a sudden rise may be more adverse than progressive exposure. 2. Dropping tanks below their max depth is very bad practise. If necessary then take actions to make it difficult to use the cylinder (e.g a bag over the 2nd stage). 3. Dont be egged on by an audience -technical dives may be more appropriately be carried out in the prescence of no distractions.
Line Management Unknown
Gas Management Major
Equipment Management Major
Equipment Failure Unknown
Training Major
Medical Unknown
Planning Unknown
Procedural Error Unknown
Cave Environment Minor
Weather Unknown
Other Factor Unknown