The word "degradable" on a bag sounds reassuring. In packaging, though, it can mean two very different things — and only one of them ends with the material actually disappearing.
Oxo-degradable plastics are conventional plastics, usually polyethylene, blended with metal-salt additives that speed up fragmentation under sunlight, heat and oxygen. The bag breaks into smaller and smaller pieces. That is not the same as biodegrading. True biodegradation means microorganisms consume the material and convert it into carbon dioxide, water and biomass within a defined time and environment. Certified compostable materials must meet standards such as ASTM D6400, EN 13432 or GB/T 19277 — including at least 90% disintegration within 12 weeks under industrial composting conditions. Oxo-degradable fragments are generally too large in molecular weight, and too water-repellent, for microbes to metabolise — so what remains is microplastic, not compost. They also fail composting standards and can contaminate recycling streams.
Regulators have acted on that distinction. The EU's Single-Use Plastics Directive (2019/904) has banned oxo-degradable plastic products from the EU market since July 2021, on the grounds that they do not properly biodegrade, contribute to microplastic pollution, are not compostable and harm recycling. In January 2024, the EU General Court upheld the ban against a legal challenge. The ban is contested by some additive manufacturers, who cite laboratory studies showing biodegradation — but the regulatory position in the EU is settled for now, and the UK still permits these products, so the rules differ by market.
For buyers, the practical rule is simple: look for a named standard — ASTM D6400, EN 13432 or GB/T 19277 — and a certification mark, and check which conditions the claim covers. A bag that only says "degradable" makes no such promise.
Disclaimer: Product descriptions, specifications, and certification references in this article are provided for general information. Compostability claims (including ASTM D6400, EN 13432, and GB/T 19277) refer to industrial composting conditions; commercial composting facilities may not be available in all communities. Certifications apply only to the specific products listed in the relevant certificates. For current certification documentation, contact Greenstar@greenstarmaterial.com.