Echoing Green Earth

Beyond the Buzzwords: Understanding Degradable, Decomposable, Biodegradable, and Compostable

3/9/2025

Beyond the Buzzwords: Understanding Degradable, Decomposable, Biodegradable, and Compostable

Ever picked up a product labeled "biodegradable" and wondered what that actually means? You're not alone. In today's eco-conscious marketplace, terms like "degradable," "decomposable," "biodegradable," and "compostable" appear everywhere—from coffee cups to shopping bags—but these words are often misused, leading to consumer confusion and sometimes outright greenwashing.

In this post, we'll cut through the jargon to explain what these sustainability terms really mean, introduce a simple framework to understand their relationships, and help you become a more informed consumer when evaluating product claims.

Introduction

The Problem with Eco-Friendly Labels

Have you ever thrown a "compostable" fork into your home compost pile, only to find it intact months later? Or purchased "eco-friendly" packaging that turned out to be just as persistent in the environment as conventional plastic?

The problem is that environmental terminology is often used loosely, without specifying crucial details like:

  • Under what conditions will this product break down?
  • How long will it take?
  • What will it break down into?

This lack of clarity isn't just frustrating—it's also harming our waste management systems and the environment. Products labeled "compostable" that end up in regular recycling streams can contaminate entire batches. Similarly, items marketed as "biodegradable" might simply break into smaller plastic pieces rather than returning to nature.

1. Understanding How Materials "Break Down"

Before diving into specific terms, it's helpful to understand the different ways materials can break down in the environment:

Physical Breakdown: This is simply the fragmentation of materials into smaller pieces without changing their chemical composition. Imagine a plastic bag that breaks apart into smaller and smaller fragments over time. Although these pieces become increasingly tiny—eventually invisible to the naked eye—they're still plastic. The material hasn't disappeared or transformed; it has merely been divided into microplastics that can enter waterways, be ingested by wildlife, and persist in the environment for centuries.

Chemical Breakdown: This involves the transformation of materials into different chemical substances. Chemical reactions like oxidation (reaction with oxygen) or hydrolysis (reaction with water) can change the structure of materials. For example, when iron rusts, it's oxidizing and forming a new compound (iron oxide). Similarly, some plastics can undergo chemical changes when exposed to UV light, though this doesn't necessarily make them environmentally harmless.

Biological Breakdown: This occurs when living organisms like bacteria, fungi, or other microorganisms consume or digest materials, converting them into simpler substances they can use for energy or growth. When this process happens completely in soil environments, these simpler substances often become available as nutrients for plants. However, the timeline and availability depend on the specific compounds involved. Some breakdown products are immediately usable by plants (like certain minerals), while others may require further processing by soil microorganisms before becoming plant-available nutrients. This nutrient cycling is what makes properly composted materials so beneficial for soil health and plant growth.

The ideal end-of-life scenario for any material is complete breakdown, where a product returns to nature's cycles by converting into:

  • Carbon dioxide and water (in aerobic conditions)
  • Methane, carbon dioxide, and water (in anaerobic conditions)
  • Biomass (microbial cells)
  • Minerals that can nourish new plant growth

Unfortunately, many products only achieve partial breakdown, leaving behind residues or microparticles that can persist in the environment for decades or centuries.

2. Definitions, Standards, and Certifications

Understanding the Spectrum: From Degradable to Home Compostable

Let's break down these terms into a clear hierarchy, from the most basic form of breakdown to the most complete:

2.1 Degradable

Definition: Degradable materials simply break apart over time—think of a plastic bag fragmenting into smaller and smaller pieces.

Common Issues: Being "degradable" is actually the lowest bar for environmental claims. Those fragments often remain in the environment as microplastics, possibly causing more harm than the original item!

Real-world example: Those "oxo-degradable" plastic bags that many countries are now banning because they create microplastic pollution.

Standards: There are no widely accepted standards governing degradability alone, which is part of the problem with this claim.

2.2 Decomposable

Definition: Decomposable materials break down into simpler chemical substances rather than just fragmenting. This breakdown can happen through biological processes (like bacteria) or non-biological ones (like sunlight or water).

Real-world example: Paper products decompose into simpler compounds, though they may still leave traces in the environment.

Standards: Like "degradable," there are no universal regulations or standards specifically for "decomposable" claims.

2.3 Biodegradable

Definition: Biodegradable materials are broken down by microorganisms into natural elements like carbon dioxide, water, and biomass. The catch? This term means very little without specifying conditions and timeframes.

The problem: A material might be biodegradable in a lab setting at high temperatures, but take decades or centuries to biodegrade in a landfill or ocean. Without specifics, "biodegradable" can be a misleading claim.

Real-world example: Many bioplastics are technically biodegradable but only under specific industrial conditions that most consumers don't have access to.

Key Standards:

  • ASTM D5511: Tests anaerobic biodegradation under high-solids conditions
  • ASTM D6691: Assesses marine biodegradability over set timeframes
  • ISO 14855: Evaluates aerobic biodegradability under controlled composting conditions

2.4 Compostable

Definition: Compostable materials biodegrade within a defined timeframe under composting conditions, leaving no toxic residue. This is biodegradability with specifics—a timeframe, conditions, and safety requirements.

Key distinction: Most "compostable" products are only compostable in industrial facilities, not your backyard compost bin.

Real-world example: Those compostable PLA cups at eco-friendly cafes require industrial composting facilities running at high temperatures (over 55°C/131°F).

Key Standards:

  • EN 13432 (EU): The European standard requiring 90% biodegradation within 6 months in industrial composting conditions
  • ASTM D6400 (US): The American standard defining requirements for compostable plastics
  • AS 4736 (Australia/NZ): Similar to EN 13432 for the Australian/New Zealand market

2.4.1 Industrially Compostable

Definition: Materials that fully degrade within high-temperature (≥55°C) industrial composting facilities but may not break down in natural environments or home compost systems.

What to look for: Certification symbols like the "seedling" logo (European standard EN 13432) or "BPI certified compostable" in the US.

The catch: If your area doesn't have industrial composting facilities, these items may still end up in landfill where they won't properly decompose.

Key Standards:

  • EN 13432 (EU): Requires 90% degradation in 6 months or less at industrial composting conditions
  • ASTM D6400 (US): Must disintegrate so that no more than 10% remains on a 2mm sieve after 12 weeks
  • BPI Certification: A widely recognized certification program for compostable products in North America

2.4.2 Home Compostable

Definition: Home compostable materials fully degrade in backyard composting conditions, which operate at lower temperatures than industrial facilities.

The gold standard: These materials break down in typical backyard compost bins within a reasonable timeframe (usually under a year).

Real-world example: Uncoated paper products, food scraps, and some specialized packaging with "home compostable" certification.

Key Standards:

  • TÜV Austria OK Compost HOME: The most widely recognized standard for home compostability
  • AS 5810 (Australia): Specifies requirements for home compostable claims in Australia
  • NF T51-800 (France): The French standard for home compostable materials

3. The Hierarchical Categorization Model (Eco-Breakdown Pyramid)

A Simple Framework: The Sustainability Pyramid

Think of these terms as a pyramid, where each level builds on the one below it and represents a series of yes/no questions about how completely a material breaks down:

  1. Degradable (Base level)
    • Question: Does it break apart physically?
    • Example: Conventional plastic that fragments into microplastics
  2. Decomposable (Second level)
    • Question: Does it break down chemically into simpler substances?
    • Example: Paper products that break down into cellulose and other compounds
  3. Biodegradable (Third level)
    • Question: Can it be broken down by living organisms?
    • Example: Some bioplastics (under the right conditions)
  4. Industrially Compostable (Fourth level)
    • Question: Will it biodegrade in industrial composting facilities?
    • Example: PLA plastic cups and utensils
  5. Home Compostable (Top level)
    • Question: Will it biodegrade in backyard compost bins?
    • Example: Uncoated paper, home compostable packaging

Environmental and Human Health Implications of "No" Answers

When a product fails at any level of this questioning hierarchy, it creates specific environmental concerns:

  • If it's not degradable: The product remains intact indefinitely, creating visible pollution
  • If it's not decomposable: It may fragment but never chemically break down
  • If it's not biodegradable: Microorganisms cannot process it, keeping it out of natural cycles
  • If it's not industrially compostable: It may contain toxins or take too long to break down
  • If it's not home compostable: It requires special industrial conditions to properly process

Why This Hierarchy Matters

Understanding where a product falls on this pyramid helps you:

  • Avoid greenwashing: Just because something is labeled "biodegradable" doesn't mean it's environmentally harmless.
  • Dispose properly: Knowing if a product requires industrial composting prevents contamination of recycling or home compost.
  • Make informed purchases: You can prioritize truly sustainable materials based on your local waste infrastructure.

Remember: The higher up the pyramid, the better for the environment—but only if disposed of correctly!

4. Greenwashing in Environmental Marketing

Spotting Greenwashing: Real-World Examples

How can you spot misleading environmental claims? Here are some common examples of greenwashing you might encounter:

4.1 Oxo-Degradable Plastics

  • Claim: "100% Biodegradable Plastic Bags"
  • Reality: These plastics fragment into microplastics but do not fully biodegrade.
  • Correct Classification: Degradable, but not decomposable or biodegradable.
  • What to look for instead: Certified compostable bags that meet industrial or home composting standards.

4.2 PLA Bioplastics

  • Claim: "Compostable PLA Cutlery"
  • Reality: PLA requires industrial composting conditions (≥55°C) and does not degrade in home composts or natural environments.
  • Correct Classification: Biodegradable and industrially compostable, but NOT home compostable.
  • What to look for instead: Clear labeling that specifies "industrial composting required" and check if your area has such facilities.

4.3 Bamboo-Based Packaging

  • Claim: "Eco-friendly bamboo fiber containers"
  • Reality: Many bamboo-based products are blended with melamine plastic, making them non-biodegradable.
  • Correct Classification: Not biodegradable if synthetic binders are present.
  • What to look for instead: 100% plant fiber products without plastic binders, or clear, specific information about the material's end-of-life behavior and composition.

4.4 "Natural" Fabrics with Synthetic Blends

  • Claim: "Natural cotton fabric"
  • Reality: Many "natural" fabrics contain synthetic fibers like polyester that shed microplastics.
  • Correct Classification: Partially biodegradable at best.
  • What to look for instead: 100% natural fibers or detailed composition information.

4.5 "Biodegradable" Plastics

  • Claim: "Biodegradable plastic packaging"
  • Reality: Without specified conditions or timeframes, this claim is essentially meaningless. Some "biodegradable" plastics only break down in controlled laboratory conditions that don't exist in natural environments.
  • Correct Classification: Claims need verification with specific standards and conditions.
  • What to look for instead: Certified compostable materials with clear disposal instructions.

5. What Can You Do As a Consumer?

While systemic change is needed to address these issues comprehensively, here are practical steps you can take today:

5.1 Look Beyond Marketing Claims

Rather than relying solely on vague environmental claims, consider:

  • Examining product composition details (ingredients or materials list)
  • Researching the company's transparency about their materials and processes
  • Understanding that while third-party certifications can be helpful, they aren't the only indicator of environmental responsibility, as certification processes can be expensive for smaller companies with truly sustainable practices

5.2 Learn to Recognize Certifications

Some trustworthy certifications to look for:

  • BPI Certified (US): Products certified for industrial composting
  • TÜV OK Compost HOME (International): Verifies home compostability
  • Seedling Logo (EU): EN 13432 certification for industrial compostability
  • Australasian Bioplastics Association (Australia/NZ): Verifies compostability claims

5.3 Know Your Local Infrastructure

  • Find out if your area has industrial composting facilities
  • Check what materials your local recycling center actually accepts
  • Consider joining community composting initiatives if you lack space for home composting

5.4 Prioritize Reduction and Reuse

Remember that even the most sustainable single-use items still require resources to produce, transport, and process:

  • Choose reusable options whenever possible
  • Support businesses that offer refill stations or package-free products
  • Invest in durable goods made from naturally biodegradable materials like wood, glass, or metal

5.5 Choose 100% Natural Materials Whenever Possible

As Echoing Green Earth has been advocating, one of the most effective actions consumers can take is replacing everyday products with those made from 100% natural materials:

  • Kitchen items: Choose wooden cutting boards, bamboo utensils without plastic binders, and pure cotton dish towels instead of synthetic blends
  • Personal care: Opt for natural loofahs, wooden hairbrushes, and cotton swabs with paper (not plastic) stems
  • Home goods: Select wool, cotton, or linen textiles without synthetic additives
  • Packaging: When single-use items are unavoidable, choose those packaged in uncoated paper, or other natural materials

The advantage of truly natural materials is that they can typically degrade completely in home compost systems after being broken down into smaller pieces. They integrate back into natural cycles without leaving persistent residues or microplastics.

These materials have served humanity for thousands of years before synthetic alternatives were developed, proving their practicality and durability when properly maintained.

5.6 Advocate for Better Labeling

Support initiatives calling for:

  • Standardized terminology and labeling requirements
  • Clear disposal instructions on packaging
  • Bans on misleading environmental claims without specific, verifiable standards

6. Conclusion

Understanding the differences between degradable, decomposable, biodegradable, and compostable materials is essential in making informed choices as a consumer. The sustainability pyramid provides a framework to evaluate environmental claims and avoid greenwashing.

As public awareness grows, we can expect more scrutiny of environmental claims and stricter regulations around labeling. Until then, approaching eco-friendly claims with healthy skepticism will help you make truly sustainable choices.

Remember that even the most compostable or biodegradable single-use item still requires resources to produce. When possible, the most sustainable choice is often reusable items made from durable, natural materials that can last for years rather than minutes.

By becoming more informed about what these terms really mean, you're taking an important step toward reducing your environmental impact and pushing for greater transparency in environmental marketing.

What misleading "eco-friendly" claims have you encountered? Share your experiences in the comments below!

Resources for Further Learning

United States:

United Kingdom:

European Union:

Global Resources:

TÜV Austria OK Compost - Information on the widely recognized home and industrial composting certifications

How to Spot Greenwashing - Earth Day Network's guide