Deterpenated or concentrated citrus oils — where terpenic by-products have been removed to increase the aromatic intensity — are specifically provided for under 330190 (concentrates of essential oils and related products) rather than under the straight citrus oil subheadings (330112–330119). The degree of processing and whether terpenic fractions have been separated are therefore key classification facts.

Essential oils used as food flavorings or in cosmetic or pharmaceutical formulations may be subject to FDA oversight depending on their intended end use. Oils imported for use in food or drug products should be accompanied by documentation supporting their intended application, and importers should be prepared for FDA examination. Consulting a licensed customs broker familiar with FDA entry procedures is advisable for regulated end uses.