I posted a link on Twitter to this post and asked “Are there any cases in which the OPCW or any other international organization has required such an action?”
One reader pointed out that in May 2014 the OPCW confirmed “the destruction of the entire declared Syrian stockpile of Isopropanol” which, though a Sarin precursor, is not a scheduled chemical under the CWC. Now, I believe that the CWC required Syria to declare its isopropanol. The convention mandates that a party declare “whether it owns or possesses any chemical weapons, or whether there are any chemical weapons located in any place under its jurisdiction or control.” The convention’s definition of “chemical weapons” includes “Toxic chemicals and their precursors, except where intended for purposes not prohibited under this Convention, as long as the types and quantities are consistent with such purposes.”
It’s also worth noting that this September 2013 OPCW EC decision required Syria to submit “further information” about the “chemical name and military designator of each chemical in its chemical weapons stockpile, including precursors and toxins, and quantities thereof.” Syria had already submitted “detailed information, including names, types, and quantities of its chemical weapons agents, types of munitions, and location and form of storage, production, and research and development facilities…”
So there’s some precedent.