A shipment qualifies as NES when it consists of mixed polymer types that cannot be separated or identified as a single resin family, or when the polymer type falls outside the enumerated headings (such as styrene or vinyl chloride polymers). If a load is predominantly one resin but contains minor contamination, classification should still reflect the dominant polymer — so accurate sorting and documentation at origin is critical.

Mixed or contaminated plastic scrap is generally subject to stricter Basel Convention controls than clean, sorted single-polymer streams. The 2019 Basel amendments placed most mixed plastic scrap in Annex II (requiring prior informed consent), while certain clean, sorted streams may qualify for less-restricted treatment. US importers should work with their logistics provider to confirm the exporting country's consent procedures before shipment.