Why compostable plastics don't decompose - 3 minutes to spot the ‘pseudo-degradable’ trap

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Update time : 2025-06-19

The “eco-friendly plastic” you buy may be deceiving you

In recent years, compostable plastic has been promoted as the “ultimate solution” to white pollution. However, many consumers are finding that the “biodegradable” bags or packaging they purchase do not decompose in the composting environment for months, and even leave microplastics behind.

In 2024, the international environmental organization Break Free From Plastic released a report stating that more than 60% of “compostable plastics” on the market do not fully degrade within the promised time frame, and that some of these products are even more harmful than traditional plastics.

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Part 1: Why Your Compostable Plastic Doesn't Break Down?

Reason 1: The material is not a real “compostable plastic”

✅ Real Compostable Plastic:

Composed of PLA (Polylactic Acid), PBAT, PHA, etc., degraded by industrial composting (high temperature + microorganisms) or home composting

Certified Standard: OK Compost INDUSTRIAL / HOME, ASTM D6400

❌ Pseudo-degradable plastics:

Oxo-degradable: contains PE+additives, only crumbles into micro-plastics (banned in the EU)

Partially starch-based plastics: a mixture of non-degradable components (e.g., PP), practically non-compostable

Typical examples:

A brand of “eco-friendly shopping bags” is labeled as A brand of “eco-friendly shopping bag” is labeled as “100% biodegradable”, but lab tests show that:

Contains 40% of traditional PE plastics

Only 15% decomposed in 18 months in composting environment

Reason 2: Degradation conditions are not met

Even if the material is acceptable, incorrect handling can lead to non-decomposition:

Degradation environment Temperature requirements Time requirements Frequently asked questions

Industrial composting 50-60°C 180 days 90% of municipalities do not have a facility

Household composting 20-30°C 6-12 months Moisture/carbon-to-nitrogen ratio imbalance

Natural environment Not applicable Hardly decomposes Disposed of by mistake into the sea/soil

Reality:

Only 35% of Europe's Reality: Only 35% of European cities have industrial composting plants

68% of “compostable plastics” in the US end up in incineration or landfills

Reason #3: False or ambiguous certifications

Some companies play with words:

Use of the word “degradable” instead of ‘compostable’ is not a good way of saying “compostable”. Degradable“ instead of ‘Compostable’

Falsifying certification marks (e.g., fake ”Green Leaf“ logo)

Concealing the small print ”Industrial Composting Only" statement

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Part II: 3 Minutes to Recognize the Pseudo-degradation Trap

Step 1: Look for Certifications (30 seconds)

✅ Real Certifications (official numbers available on the website):

Industrial Composting: OK Compost INDUSTRIAL, ASTM D6400

Home Composting: OK Compost HOME, AS 5810

Others: BPI (USA), TÜV Austria (EU)

❌ High-risk labels:

“Biodegradable” (no specific criteria)

“Environmentally friendly material” (no certification)

"Oxo-biodegradable “ (Oxo-biodegradable)

Step 2: Check Ingredients (60 seconds)

Safe Ingredients: PLA, PBAT, PHA, Nano-cellulose

Hazardous Ingredients: PE, PP, PS (traditional plastics)

Ambiguous Ingredients: ”Bio-based" (may mix with non (may mix with non-degradable materials)

Quick test:

Light a small piece of material with a lighter:

True PLA/PBAT: burns slowly, sweet smell, brittle ashes

Contains PE/PP: burns quickly, black smoke, drips plastic liquid

Step 3: Ask about disposal (30 seconds)

Confirm with the merchant:

“Does this product have a complementary composting facility in my city?”

“If composting is not possible, is there a recycling program?”

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Part III: Recommendations for Truly Compostable Plastics (measured in 2024)

1. Home Composting Applicable

BioBag 3 Gallon (PLA+PBAT):

OK Compost HOME certified

Measured home composting fully decomposed in 4 months

EcoSafe Compostable Bags (cornstarch-based):

Tear-resistant, suitable for food waste collection

2. Industrial Composting Applicable

TIPA Flexible Packaging (PLA composite film):

Used for snack packaging, 6 weeks degradation

NatureWorks Ingeo (PLA resin):

Heat-resistant cup lidding material, Starbucks supplier

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Part IV: Industry change and consumer action

Policy upgrades

EU: from 2025, all “compostable” products must be labeled with the method of treatment

China: new GB/T 41010-2024 standard to crack down on false degradation promotion

Reporting of false products: via BPI website or 12315 platform

Supporting true eco-brands: eg. Ecovative (mycelium packaging)

Promote local composting: propose to municipalities to build treatment facilities

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Why compostable plastics don't decompose - 3 minutes to spot the ‘pseudo-degradable’ trap

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