Glycolic acid, a hydroxy-carboxylic acid, is generally classifiable under this heading when not covered by a more specific provision. End use does not change the chemical classification, but it does affect downstream regulatory requirements: glycolic acid in cosmetic formulations is subject to FDA oversight, while industrial-grade material used as a descaler may face different documentation expectations. Importers should confirm the applicable grade and intended use with their customs broker.

The lactic/tartaric/citric heading is reserved for those three named acids and their salts and esters specifically. Any other carboxylic acid whose only additional oxygen function is a hydroxyl group — such as mandelic acid or glyceric acid — falls under this NES heading. When a product could plausibly fit either, the CAS number and structural formula should be reviewed against the explicit named-acid list before classification is finalized.