Hmm, interesting indeed:
a. Steel cylinders
b. Lost into the ocean during the explosion
c. Nowhere in
the report is the word
"corrosion" mentioned
There is also the other possibility that the neoprene rubber between the retaining straps and bottles was either missing or worn very badly allowing chaffing of the retaining strap and the bottle. High vibrations, metal rubbing against metal, metal wearing thinner, then too thin to retain the 1600-1700psi pressurised oxygen = KABOOM!
During the mandatory inspection of all oxy bottles on QF's 744 aircraft after the event and many years after the FAA service bulletins to check for oxygen bottles, there were a few of the retaining straps that were found to have the neoprene rubber missing.
Nothing to do with filling nitrogen into oxygen cylinders.
Just a thought.