This is for you, @Emunator.
This rig is based off an item on the TF2 Workshop of the same name. I've always thought it looked cool, so I decided to rig it as practice.
One could use the inhaler to survive in a radioactive area or a particularly toxic YouTube comments section.
The rig has a separate mask and hood, so if you like one more than the other, you should be able to use it alone.
You can download the rig here.