This is my first post on this forum, I am not a pilot (would love to learn) but I am an experienced diver and know how serious an oxygen fire could be.
An in-flight oxygen fire would be a nightmare to deal with, I don't think anyone is going to stay in a cockpit with a nearby oxygen fire, just the heat given off would drive them out.
This is an incident that happened in USA some years ago. In the fifth picture you can see the remains of one of the aluminium cylinders, burst and melted.
22-May-06 Palm Bay, Florida. Why we don't fill our own tanks!
As someone who has spent a fair amount of time looking for ship wrecks in <50m of water I have an inkling of the scale of the search task. What worries me is the complete lack of any floating debris.