What it is
A recommendation, not an obligation
STANREC 4743 is a NATO Standardization Recommendation on biological warfare agent challenge levels. The distinction that matters most is in its name: unlike a STANAG, a STANREC does not commit a nation to ratify anything. NATO's own text is explicit that this STANREC "is a non-binding document employed on a voluntary basis and does not require commitment of the nations to implement the standards which are listed in it" - a voluntary basis, not a ratification obligation. Nothing in this document creates a duty for a supplier to sign up to directly.
What it recommends
The document's aim is "to list recommended practices regarding: Deposition and dosage levels of biological warfare agents to which protective equipment and procedures for NATO forces should be designed to allow unaffected operations." Its recommendation is a single document: AEP-72, Volume IV, Edition A. STANREC 4743 does not expand on what AEP-72 Volume IV requires; the point of this cover document is to name it, not to reproduce it.
The same clause draws a distinction worth keeping straight: the levels are "intended to provide design guidelines," and the document is explicit that they are not to be used for "risk assessment". They are an input to design, not a method for assessing risk.
A family of related CBRN standards
Alongside the recommendation, the cover names twenty other NATO standardization documents without saying any of them bind anything here. Three are the other volumes of the same AEP-72 series - STANREC 4726 (chemical, biological and TIC challenge levels, Vol. 1), STANREC 4741 (chemical agent challenge levels, Vol. 2) and STANREC 4742 (toxic industrial chemicals challenge levels, Vol. 3). The rest cover the wider CBRN protective-equipment family: protective clothing (AEP-38, via STANREC 4548), respirators (AEP-71, via STANREC 4725), protective masks (AEP-73, via STANREC 4727), collective protection (AEP-54, via STANREC 4634), and CBRN defence on operations (ATP-3.8.1, via STANAG 2521 and STANAG 2522). Our standards explorer lists the rest.
A new recommendation, not a replacement
STANREC 4743 supersedes nothing: "This STANREC does not supersede any document." It is a fresh recommendation, not a consolidation of an earlier agreement.
Where the actual requirements live
STANREC 4743 has no clauses of its own to audit against. It is supervised under CNAD's AC/225 NATO Army Armaments Group (NAAG) and the Joint CBRN Capability Development Group. The document is reviewed at least once every three years, with the result recorded in the NATO Standardization Document Database; that review is the only ongoing mechanism it names, and it checks the document's own currency, not a piece of equipment or an organisation. The biological warfare agent challenge levels themselves sit inside AEP-72, Volume IV, not here.