Dallas schrieb:

"Oxygen is oxygen. It is the substance that matters, not the intended
purpose. These days, welding, medical, and aviation oxygen are exactly the
same. All three come from the same tank of liquid oxygen (LOX). The
liquified form is the cleanest, purest, driest form of oxygen (or any
substance) you'll find anywhere."

Sure. But you don't care about the oxygen in the manufactorer's tank,
it's the oxygen in the bottle that you care about. It's the filling
process which makes all the difference.