As Don Holden suggests, the generator USP oxygen (90 - 96%) may be used as a supplemental supply, such as an EOSC source, in the event of a catastrophic loss of the primary supply of the conventional USP oxygen (99 - 100%) remote bulk supply.
Thanks to Don Holden, I was able to learn some of these facts from a letter from HHS dated January 7, 2011 with an "Indications for Use" attachment. This letter states that the generator USP oxygen is "substantially equivalent" only as it applies to the conditions in the attached "indications for use".
In addition, as I read the attached "Indications for Use" attachment, the military is allowed to use this generator USP oxygen in times of war and peace.
This is my "read" and I am grateful to Don for bringing this to my attention.