Portable O2 bottles

[ultrarunner]

Maybe if your 91 its exempted. It isnt with us. We primarily fly 135 and occationally fly 91. Oxygen is considered HAZMAT. Its a Class 2.2 Non flammable gas. However dependant on your company OpSpec's and whether or not you are operating Pt 135 will determine what action must be taken to deem the flight satisfactory.

But you're exempted on the 135 side if you're flying an aircraft that the OEM supplies with a POB.....

With that being the case, I'd say it would be easy enough for anyone to get an exemption.