Synthetic fibers (polyester, nylon, acrylic, polypropylene) are derived from petrochemical sources, while artificial fibers (rayon, viscose, lyocell, modal) are made from regenerated cellulose. Schedule B treats these as distinct categories, and the predominant fiber by weight determines the heading. Blended fabrics require a weight analysis to confirm which fiber type governs classification.

While the US eliminated most textile quotas following the expiration of the Multi-Fiber Arrangement, several destination countries maintain their own import licensing, visa, or safeguard mechanisms for textile products. Exporters should verify current requirements with the destination country's customs authority, particularly for markets with active textile safeguard investigations or bilateral restraint arrangements.