Emergency O2 tanks shouldn't be pure O2

[Clarks]

On tg emergency tanks last just a few minutes, it's stupid. You can top them up pretty easily, but why does it have to be one more chore.
Maybe it will make a few people stop to don internals first thing in the round, but c'mon...
Emergency or proper tank is really a choice of backpack versus belt.

Most of the non-essential crew will no longer start with emergency tanks in their bags unless they are lucky. There are a few more emergency lockers around to compensate for this.

Always spawning with a tank in the backpack did feel a little strange.