9902.05.38 - Sodium hydrogen methylarsonate (CAS No. 2163-80-6) (provided for in subheading 2931.90.90)

This HTS classification, 9902.05.38, specifically designates Sodium hydrogen methylarsonate (CAS No. 2163-80-6). This chemical compound is an organoarsenic compound used primarily as an herbicide. Its inclusion within Chapter 99 signifies that it is subject to temporary legislation, modifications proclaimed pursuant to trade agreements, or additional import restrictions under Section 22 of the Agricultural Adjustment Act.

Unlike the preceding categories in Chapter 99, which often address broad categories of temporary trade measures or specific, potentially large-volume goods subject to unique import rules, 9902.05.38 pertains to a singular, specific chemical substance. Its identification is further refined by its Chemical Abstracts Service (CAS) registry number, ensuring precise classification. The parenthetical note "(provided for in subheading 2931.90.90)" is crucial, indicating that while this item falls under temporary measures in Chapter 99, its general classification under permanent tariff headings is within subheading 2931.90.90, which covers other organo-inorganic compounds.

As a leaf node, this classification has no further subcategories. The defining characteristic for classification under 9902.05.38 is the precise identification of the chemical compound as Sodium hydrogen methylarsonate, along with its corresponding CAS number. Importers must verify that the imported substance precisely matches this description and that any associated temporary restrictions or conditions outlined in Chapter 99 are met.