The flashback arrestor are there to stop a pressure wave/explosion to travel back into a tank/storage device and rupture something causing flammable gas leaking.
Gases themself are non flammable when there is no Oxygen available ref. the “fire triangle”
The amount of Oxygen needed to be combustible depends on the gas. Acetylene are the worst I believe, the others are more “benign” in that they are combustible only in a narrow range.
Thus an actual explosion of a tank/storage device is highly unlikely.
But a leak of flammable gas may cause catastrophic fires anyway.
A leakage of Oxygen do not pose the same amount of immideate danger, but if left unchecked, may contribute to a fire if it ever happens. I think we were thaught that a 1% increase on Oxygen doubled the rate/speed of burning.
The need for flashback arrestors, should not be neccessary on Oxygen concentrators. Because if there are a flashback that breaks anything on the Oxygen side, you should more or less notice it immideatly due to lack of oxygen at the torch.
You will then have ample time to take measures.
What regulatory rules may or may not say, that is a completely different ballgame
Acetylene, even if it is good in many ways,
differ a bit from other flammable gases.
Because it can decompose catastrophically without Oxygen if sufficiently shocked or overheated.
Tanks should always be kept/stored outside if possible.