Commerce Department CWC regulations designate specific Schedule 1, 2, and 3 chemicals. Within this heading, methylphosphonic acid (293144), methylphosphonic dichloride (293151), propylphosphonic dichloride (293152), and DMMP (293141) are among the enumerated CWC-scheduled substances. Importers should cross-reference the specific subheading against the current Commerce CWC control list and obtain the required end-use certificate before shipment.

Tributyltin (TBT) compounds covered under 293120 face severe use restrictions globally, including an IMO ban on antifouling paints and EPA restrictions on biocidal applications. While some specialty industrial uses remain, import volumes are limited. Importers should verify that the intended end use complies with EPA TSCA and any applicable state-level restrictions before clearing a shipment.