Nitrox fills

[tpscuba]

We use synthetic oil and we dump all the air out we should have removed the Nitrox sticker, but we must have missed it.
As far as a regulation I am looking for it, if it is there.
The training we conduct is for cylinder inspection certification and Nitrox never came up in the classes. These classes are directed to a good and complete inspection of scuba and SCBA tanks for cracks, pits, bulges, properly stamped tanks (we had one come through where the individual tried to stamp his own hydro) and electronic testing.
We have a course on Sat. Jan 17th 2004 If I don't find an answer by then I will ask about it.
Amendment 1
I got a hold of the Department of Transportation and the gentleman that assisted me said there is no regulation that states when going from one breathing gas to another ie; Nitrox back to air, but there is a safety factor up to the filling station. We take the stickers off (unless we miss it) so that they would need to be O2 cleaned before filling again. The big thing I would say to watch is if you are filling better than 40% then the o-rings need to be totally changed, but for safety we change them for under 40% whats a few dollars when it comes to your life (Murphy's Law).