Subheading 780191 applies specifically when antimony is the principal alloying element by weight. If another element — such as calcium or tin — is the dominant alloying addition, the material falls under 780199 as other unwrought lead alloy.

Unwrought lead is not subject to mandatory admissibility review by a food or drug agency, but EPA regulations governing lead as a hazardous substance may affect handling, storage, and downstream use. Importers should also verify whether any state-level restrictions apply to the intended end use.