The ASTM D6400 standard is the definitive guide for compostable plastics in the United States. It provides a scientific framework to ensure that materials labeled as "compostable" actually fulfill their environmental promise without harming the soil.
1. Definition — What Is ASTM D6400?
The ASTM D6400 compostable plastics standard defines how plastic materials must perform under industrial composting conditions to be labeled as compostable.
According to ASTM International (2020), the D6400 standard specifies compostability requirements for plastics that can be aerobically degraded into CO₂, water, and biomass within 180 days, leaving no toxic residue.
This certification is recognized globally as the benchmark for ensuring environmental safety and material transparency in compostable packaging. Summary: ASTM D6400 confirms that a compostable product truly returns to nature under controlled composting processes.
[Image of industrial composting process]2. Testing Scope — Key Parameters of Certification
Before a material can be certified under the ASTM compost standard, it must pass strict laboratory tests that evaluate four core areas:
- Biodegradation: At least 90% carbon conversion to CO₂ within 180 days.
- Disintegration: No visible fragments remain after 12 weeks in compost.
- Toxicity Test: No heavy metals or plant-growth inhibition.
- Compost Quality: The composted material must support microbial and plant life.
Third-party organizations such as the Biodegradable Products Institute (BPI) and TÜV Austria verify compliance through these standardized testing methods, ensuring consistency across industrial composting systems.
3. Why It Matters — Environmental and Industry Impact
ASTM D6400 turns "compostability" from a marketing term into a verifiable environmental standard. It prevents misleading green claims (greenwashing) and helps manufacturers, regulators, and consumers trust that certified materials will safely decompose.
By setting a clear scientific benchmark, the standard supports industrial composting systems and reduces landfill waste. Furthermore, it promotes innovation in bio-based materials, encourages PFAS-free design, and aligns global sustainability practices under one consistent framework.
4. ASTM D6400 vs EN 13432 — Understanding Regional Standards
While both standards establish compostability guidelines, they apply to different regions and utilize slightly different timelines.
| Feature | ASTM D6400 (U.S.) | EN 13432 (EU) |
|---|---|---|
| Authority | ASTM International | European Committee for Standardization (CEN) |
| Composting Environment | Industrial (58 °C) | Industrial (58 °C) |
| Degradation Period | ≤ 180 days | ≤ 90 days |
| Heavy Metal Test | Required | Required |
| Certification Body | BPI | TÜV Austria |
Conclusion: Although EN 13432 focuses on Europe and ASTM D6400 on North America, both verify full biodegradation and ecological safety, creating global consistency in sustainable product standards.
