Heading 2501 explicitly includes salt in aqueous solution (brine), provided the dissolved substance is sodium chloride with only permitted additives such as anti-caking agents. If the solution contains other dissolved substances at levels that give it a distinct character or use — for example, a mineral-enriched brine marketed as a functional ingredient — it may shift to a more specific chemical or food-preparation heading. The heading notes and CBP rulings on brine composition are the authoritative reference.

Denaturated salt — sodium chloride rendered unfit for human consumption by the addition of approved denaturants — is still classified under 2501 but may require documentation confirming the denaturant type and concentration, particularly if the salt is destined for industrial or agricultural use where food-grade diversion is a concern. FDA and state agricultural agencies may have additional requirements depending on the denaturant used.