Isn't it explosive because it is under pressure or is in liquid form?
Oxygen used in cutting or medical isn't in liquid form. It is compressed gas. Acetylene and lpg can be liquid. Commercial oxygen is an oxidizer, meant to be added to another gas for maximum effectiveness. It is around 1500 psi in the bottles I own, but it is regulated down to about 30-50 psi for welding and cutting. I can go to the garage and hold a cig in front of the oxygen bottle, and get a pic if anyone wants.