What it is
STANAG 2558 is a NATO Standardization Agreement, not a technical specification in its own right. It is the agreement by which NATO nations commit to implement a publication, and here that publication is AMedP-8.17, Edition A. The STANAG itself is short: a letter of promulgation, the agreement to implement, and the machinery for ratification, implementation and review. The substance, the actual minimum standards for producing oxygen 93 per cent, lives in AMedP-8.17, which has its own record.
The interoperability problem it answers
The agreement responds to a stated interoperability requirement: to define the minimum standards for oxygen 93 per cent produced on operations. It is meant to contribute "to enhance the effectiveness of NATO forces when conducting joint operations, through the adoption of a uniform and safe level of production of oxygen 93 per cent for medical life-support applications" and "to facilitate the exchange of medical oxygen 93 per cent bottles between member nations." Neither the production process nor any purity, pressure or test figure beyond the 93 per cent named in the title is printed in this cover; that detail sits in AMedP-8.17.
What ratifying nations commit to
Participating nations agree to implement "the following standard": AMedP-8.17, Edition A. They also agree "to use AMedP-8.17 as a manual for minimum standards for oxygen 93 per cent produced during field operations," and agree that "the installations for the production of oxygen 93 per cent during field operations shall meet the minimum requirements detailed in this AMedP-8.17." Their ratification and implementation decisions are recorded by NATO in the NATO Standardization Document Database, not restated here. Partner nations are separately invited to adopt the STANAG. This is Edition 1, and the cover states plainly that it "does not supersede any document."
How it takes effect and is reviewed
A STANAG does not bind a supplier directly. It is "effective upon receipt and ready to be used by the implementing Nations and NATO bodies", meaning a nation's own instructions, or a contract that invokes AMedP-8.17, are what actually create a requirement for an organisation to meet. Nations report their effective implementation using the form in Annex H to AAP-03(J); partner nations use Annex G of the same publication. The STANAG "is to be reviewed at least once every three years", and any nation or NATO body can propose a change at any time to the tasking authority for processing at the next review. The tasking authority is named in the cover by its abbreviations, MCMedSB and MedStd; the custodian named is Germany, with a panel abbreviated MMMP.
Related documents
This cover names AMedP-8.17 as the standard it puts into force; that is where the requirement itself lives, and it is not restated here. It also lists other related documents for context, with no further statement of how each applies: STANAG 2121 (cross-servicing of medical gas cylinders, covering AMedP-1.19), STANAG 1458 (diving gas quality, covering ADivP-04), STANAG 3198 (functional requirements of aircraft oxygen equipment and pressure suits, covering AAMedP-1.3), European Pharmacopoeia 8.0, the United States Pharmacopeia (USP 38) National Formulary (NF), two EU Council directives, and ISO/FDIS 10083. None of that last group is in our catalogue, so there is no page or explorer entry to link.