2918.99.18.00 - 4-(4-Chloro-2-methylphenoxy) butyric acid;p-Chlorophenoxyacetic acid; and 2-(2,4-Dichlorophenoxy) propionic acid

This HTS category encompasses specific carboxylic acids with additional oxygen functions, and their derivatives, that are primarily used as pesticides. The listed compounds—4-(4-Chloro-2-methylphenoxy) butyric acid; p-Chlorophenoxyacetic acid; and 2-(2,4-Dichlorophenoxy) propionic acid—are synthesized organic chemicals characterized by their distinct chemical structures and their application in agricultural and horticultural pest control. Their inclusion here is based on their pesticidal function rather than solely on their chemical nomenclature as carboxylic acids.

This category is distinguished from its sibling, 2918.99.20, which covers "Other" carboxylic acids with additional oxygen functions that do not possess a primary pesticidal application. While both categories fall under the broader scope of other carboxylic acids with additional oxygen functions, the defining criterion for classification within 2918.99.18 is the intended use as a pesticide.

As this is a leaf node in the HTS, there are no further subcategories. Classification within 2918.99.18 is therefore determined by identifying the specific chemical compounds listed in the description and confirming their documented use as pesticides. This ensures precise tariff application for these agriculturally significant chemicals.