Originally Posted by
Ascend Charlie
Yes, but different responses to an emergency if a medical bottle starts leaking, or the pilots' system goes berserk.
There is an urban myth about a fighter pilot whose moustache caught fire in his mask when the system got to 100% at altitude - he had been eating peanut butter for breakfast.
That is exactly that, a myth. Pure oxygen is not a problem under 10 bar of pressure. True, it helps with burning, but if it comes to that, you already have much bigger problems on your hand.
Like EXDAC already said, aero systems deliver oxygen at slightly above ambient level.
Unless it's explosive leak, oxy leak is not a problem in itself.