Schedule 3 of the Chemical Weapons Convention

Schedule 3 substances, in the sense of the Chemical Weapons Convention, are chemicals which have large-scale industrial uses, but are feasible to use as toxic chemical weapons (Part A) or manufacturing precursors (Part B). Plants which manufacture more than 30 tonnes per year must be declared and can be inspected as per Part VIII of the "Verification Annex", and there are restrictions on export to countries which are not CWC signatories.

Source: Wikipedia — Schedule 3 of the Chemical Weapons Convention (CC BY-SA 4.0)