German online magazine SPIEGEL is quoting an "Expert", "Most probably one of the oxygen cylinders exploded, it doesn't look like corrosion."
Well, there are "experts"... and then there are people who actually know what they are talking about
Have a look at the threads after the 744 electrical bus failure a few months ago. Same initial whingeing. "Must have been cheap Asian workers with their staple guns that nearly caused our plane to crash". Whoops, looky here, it was just checked out in Avalon. (Please, don't take my word for it, go and look at the threads yourself.)
I think you need to look back a little further... The rot at Qantas started when the "new world" bosses hacked up Sydney engineering and moved major maintenance to Avalon and sacked a large number of experienced workers. With everything in Sydney, you used to have the international & domestic airports, hangars, stores, overhaul shops, engine lines, technical help offices, etc, all within a few hundred metres of each other.... Now it's a few hundred miles. Need a spare part for an aircraft in Sydney.. no. .sorry.. the part is in Avalon.
Major maintenance (in Sydney) used to be a breeding ground for top engineers... Apprentices and tradesmen had the opportunity to be trained as licenced engineers (c/o the company) and work up through the ranks. Now the same people are probably stuck in dead end/"production line" jobs in Avalon. Morale is probably at an all time low.