1515 - Other fixed vegetable or microbial fats and oils (including jojoba oil) and their fractions, whether or not refined, but not chemically modified:

This HTS category, 1515, encompasses fixed vegetable or microbial fats and oils, along with their respective fractions, that have not undergone chemical modification. This includes a wide array of non-edible oils and their derivatives, as well as the notable exception of jojoba oil, which, despite being technically a liquid wax ester, is classified here due to its unique properties and common trade usage. The key defining characteristic is that these fats and oils are "fixed," meaning they are solid or semi-solid at ambient temperatures and do not readily volatilize, distinguishing them from essential oils.

Category 1515 serves as a residual grouping for vegetable and microbial fats and oils not specifically enumerated in preceding headings within Chapter 15. For instance, while Category 1500 might cover more commonly consumed edible vegetable oils, 1515 is for those with different primary uses or origins, or those not fitting into more specific subheadings. It also explicitly excludes chemically modified oils, which would fall under different HTS classifications.

Within this broad category, several subheadings provide more granular classification based on the specific type of oil. These include distinct classifications for linseed oil, corn (maize) oil, and castor oil, each with its own set of properties and applications. The inclusion of microbial fats and oils highlights the evolving landscape of fat and oil production. The residual "Other" subheading (1515.90) captures any remaining fixed vegetable or microbial fats and oils and their fractions that do not fit into the more specifically defined subcategories, ensuring comprehensive coverage.