Chapter 15 covers waxes of animal origin (such as beeswax and spermaceti) and vegetable origin (such as carnauba wax). Heading 3404 is reserved for chemically synthesized or blended waxes — including polyethylene wax, Fischer-Tropsch wax, and PEG waxes — that do not occur naturally. A prepared wax that blends natural and synthetic components is classified based on its essential character.

Pure or substantially pure paraffin wax from petroleum refining classifies in Chapter 27. If the paraffin is blended with other waxes or additives to create a prepared wax with specific performance properties, it may shift into heading 3404. The degree of processing and the presence of functional additives are the determining factors.