Do these planes have oxygen masks?
(Do these planes have oxygen masks?)
Decompression takes place in less than 10 seconds depending on the altitude.
I would assume any aircraft that can fly above a certain level would have them but I don’t know for sure. When I was skydiving in the 1980s, I was going to participate in a jump over 15,000 feet which required everyone on the non-pressurized aircraft have their own oxygen supplies for the jump.