Using 100% oxygen for offgasing

[Chuck_Northrup]

As long as you respect your MOD, and are certified in its use, you can use any combination of gases you would like and maintain a safe profile 

While O2 is normally used in decompression diving (as you would learn in Advanced Nitrox and Decompression Procedures) to off gas more efficiently in the shallower depths and accelerate decompression, I would not see it as inappropriate for recreational use.  After all many rebreathers like the LAR V and the C-96 are oxygen CCR's which means they use only 100% O2 

Using an oxygen CCR means you can only dive to 20 fsw...but you could also dive immediately before flying  :o  You would actually surface from the dive with LESS nitrogen in your system than when you started  8)