NAICS assigns plastics articles to specific 6-digit categories (bottles, pipe, foam, film, etc.) first; only products that do not fit those defined categories are captured in the residual 'other' groupings. For HTS classification purposes, the physical form, primary material, and end-use function all factor into the correct tariff line.

When a plastics product undergoes substantial transformation across multiple countries—for example, resin compounded in one country and molded in another—the country of origin is determined by where the last substantial transformation occurred. A binding ruling request to CBP can provide certainty before large-volume shipments begin.