Brian wrote on 11/11/2019 9:13 PM:
It would seem to me that contaminated oxygen used to weld the airplane together could be Fatal also.

I was told many years ago by a gas supplier, that welding oxygen has strict
contamination requirements, and that we can safely breathe oxygen that a welder
would reject.

Concerns over water freezing in the regulator seem exaggerated: even if a bottle
had only humid air in it before filling, that air will be only 15psi/2000psi =
0.0075 = 0.75% of the bottle after filling, reducing the humidity by over a 100.
The dewpoint is then well below -30F, so it's not going to freeze in the regulator.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1