The Basics of TÜV OK Compost Certification Tiers

TÜV Austria‘s OK Compost certification family is the most widely-recognized European compostability mark, and one of the most globally cited in compostable packaging. A product carrying any of the OK Compost marks has been independently tested against defined criteria by an accredited certification body. The marks appear on millions of compostable foodware items, packaging products, and consumer goods worldwide.

The structure of the OK Compost family has more tiers than most buyers realize. The certification umbrella includes OK Compost INDUSTRIAL (the main industrial composting mark), OK Compost HOME (home composting at lower temperatures), OK Bio-Based (biobased content rather than compostability), OK Soil Biodegradable (in soil rather than compost), OK Marine Biodegradable, OK Water Biodegradable, and others. Each tests different end-of-life conditions or product attributes. A product carrying one mark doesn’t automatically carry others.

For B2B buyers, foodservice operators, and product brands evaluating supplier claims, knowing which OK Compost mark actually means what — and which doesn’t necessarily imply the others — is the difference between specifying packaging that genuinely fits your operational end-of-life pathway and getting caught in a procurement audit or customer complaint.

This is the working basics. Each tier explained, what it tests, where it applies, and how the tiers fit together in a comprehensive packaging certification program.

TÜV Austria as the Certification Body

Background context first. TÜV Austria is part of the broader TÜV (Technischer Überwachungsverein) family of German-language technical inspection organizations. TÜV Austria operates a major certification division specifically for sustainable products, including the OK Compost program. The OK Compost program was originally developed and operated by Vinçotte (a Belgian certification body) before TÜV Austria acquired the program in 2018.

The OK Compost certification:

• Is independent (TÜV Austria isn’t selling products; they’re testing and certifying them)
• Uses laboratory testing per defined protocols
• Requires ongoing renewal (typically annual)
• Maintains a public database of certified products
• Has international recognition, particularly in Europe

For products marketed in Europe especially, OK Compost certification is among the most rigorous and widely-accepted compostability marks available. The certification structure has been refined over multiple decades.

OK Compost INDUSTRIAL: The Primary Mark

The flagship certification. Tests whether a product breaks down in industrial composting facility conditions and produces acceptable compost.

Testing protocol: based on EN 13432 standard. Tests:

• Biodegradation: at least 90% conversion of organic carbon to CO2 within 6 months under controlled conditions (58°C ± 2°C).
• Disintegration: at least 90% of test material passes through 2mm sieve after 12 weeks of pilot-scale composting.
• Ecotoxicity: finished compost must not negatively affect plant growth (OECD 208 test with two plant species).
• Heavy metals: concentrations capped at defined CEN limits across 11 elements (zinc, copper, nickel, cadmium, lead, mercury, chromium, molybdenum, selenium, arsenic, fluorine).
• Hazardous substances: defined limits on dangerous substances.

What products typically carry it: bagasse plates, PLA-coated paper cups, compostable bags, clear PLA cups, food containers, takeaway boxes — virtually all commercial compostable foodware made for industrial-composting end-of-life.

Equivalent standards:
– ASTM D6400 (US standard, similar test approach)
– ISO 17088 (international)
– AS 4736 (Australia)
– BPI Compostable Logo (US, ASTM D6400 based)

Geographic relevance: most relevant for European markets where OK Compost is the dominant industrial-compostability mark. In the US, BPI is more common; products often carry both for international supply chains.

What it does not certify: home composting capability, marine biodegradability, soil biodegradability, biobased content. A product with only OK Compost INDUSTRIAL needs a different mark for any of those other claims.

OK Compost HOME: The Stricter Tier

Home composting requires breakdown in cooler, slower, less controlled conditions than industrial composting. The OK Compost HOME certification tests this directly.

Testing protocol: similar structure to OK Compost INDUSTRIAL but with adjusted parameters reflecting home compost conditions:

• Test temperature: 20-30°C (vs 58°C for industrial). This is the key difference — home compost runs ambient or slightly above, not at the thermophilic temperatures of industrial facilities.
• Test duration: typically extended timeframes accounting for slower decomposition at lower temperatures.
• Disintegration and biodegradation thresholds: similar 90% targets but achieved over longer periods.
• Ecotoxicity and heavy metals: same as INDUSTRIAL.

Why it’s a stricter test: most products that pass INDUSTRIAL fail HOME because they don’t break down at lower temperatures. PLA-based products particularly struggle. Pure paper, bagasse, and PHA-based products are more likely to pass.

What products typically carry it: products specifically designed for home compost end-of-life. Some bagasse and paper plates. Some PHA-based packaging. Some specialty compostable bags marketed for home compost. Less common across the broader category.

Geographic relevance: increasingly important in markets where home composting is widespread. Important for B2B operators selling to consumer markets where industrial composting infrastructure isn’t universal.

What it does not certify: industrial composting (though products with OK Compost HOME typically also pass INDUSTRIAL since the test conditions are stricter for HOME). Marine, soil, water environments.

Practical implication: a product carrying OK Compost HOME is suitable for a wide range of disposal scenarios. A product carrying only INDUSTRIAL is suitable only where industrial composting infrastructure is available.

OK Bio-Based: Measuring Renewable Content

This certification doesn’t test compostability at all. It tests how much of the product is made from biobased (renewable) materials versus fossil-derived materials.

Testing protocol: uses carbon-14 isotope testing. Biobased carbon (from recently-grown plants) has different carbon-14 ratios than fossil-derived carbon (from ancient organic material). The test measures the ratio and calculates the percentage of biobased content.

Tier structure: OK Bio-Based has multiple tiers based on biobased percentage:
– 4 stars: 80%+ biobased
– 3 stars: 60-80%
– 2 stars: 40-60%
– 1 star: 20-40%

What products typically carry it: bioplastics, biobased polymers, products marketed on biobased content rather than compostability specifically. PLA products, PHA products, bio-based PE.

Geographic relevance: useful in markets prioritizing biobased content for various reasons (carbon footprint, supply chain resilience, marketing claims). Required or favored in certain government procurement programs.

Important distinction from compostability: a product can be biobased without being compostable. Bio-based PE (bio-derived polyethylene) is biobased but not compostable. A product can also be compostable without being entirely biobased (some compostable products use a mix of biobased and fossil-derived components).

What it does not certify: compostability, biodegradability in any environment, end-of-life behavior beyond manufacturing input.

OK Soil Biodegradable

Tests whether a product breaks down in soil conditions specifically (not compost facility conditions).

Testing protocol: similar biodegradation thresholds to OK Compost INDUSTRIAL but tested at soil temperatures and conditions:
– Test temperature: typically 20-28°C (ambient soil temperature range).
– Test duration: 24 months for full biodegradation in soil.
– Threshold: at least 90% biodegradation within the test timeframe.

What products typically carry it: agricultural mulch films, garden products designed to break down in soil, slow-release compost amendments. Less common in foodservice categories.

Why this matters: a product that biodegrades in industrial compost may not biodegrade in soil. Soil microbial communities are different from compost microbial communities, and the temperature range is different.

Geographic relevance: agricultural markets primarily. Some specialty consumer applications.

What it does not certify: compostability in industrial or home compost facilities (though some overlap exists). Marine or water biodegradability.

OK Marine Biodegradable

Tests biodegradation in marine (ocean) environments. Particularly relevant for products that may end up in ocean waters.

Testing protocol: tests biodegradation in marine conditions at relevant ocean temperatures:
– Test temperature: typically 25°C (warm ocean) or lower depending on protocol.
– Test duration: extended timeframes reflecting ocean biodegradation rates.
– Threshold: defined biodegradation percentages within the test period.

What products typically carry it: PHA-based packaging, some specialty bioplastics, certain natural fiber products. The list is shorter than OK Compost INDUSTRIAL because marine conditions are more demanding.

Why this matters: a substantial fraction of plastic and packaging waste ends up in marine environments through accidental release, runoff, or improper disposal. Products that biodegrade in marine conditions reduce the persistent-microplastic concern from those pathways.

Geographic relevance: increasingly important in coastal markets and for products with marine-disposal risk (boats, beaches, fishing operations). Some retailers prioritize marine-biodegradable packaging for specific products.

What it does not certify: compostability, soil biodegradability, freshwater biodegradability (though there’s some overlap with OK Water Biodegradable).

OK Water Biodegradable

Tests biodegradation in freshwater conditions (rivers, lakes, ponds).

Testing protocol: similar in structure to OK Marine Biodegradable but tested in freshwater conditions:
– Different microbial communities than marine.
– Different temperature and chemistry profiles.
– Defined biodegradation thresholds.

What products typically carry it: products with potential freshwater disposal pathways. Less common than OK Marine but present in specialty categories.

Why distinct from OK Marine: freshwater and marine environments have different chemistry, salinity, microbial communities, and temperature. A product passing one test doesn’t automatically pass the other. Certifying both gives full coverage.

Geographic relevance: relevant for products distributed in inland markets where freshwater rather than marine is the disposal-pathway concern.

OK Compost SEEDLING (the Visual Mark)

A simpler tier — the “Seedling logo” is the visual mark used by European Bioplastics that ties to OK Compost INDUSTRIAL certification. It’s not strictly a separate certification; it’s a brand mark used by European Bioplastics on products that hold OK Compost INDUSTRIAL or equivalent certification.

What it indicates: the product is industrial-compostable. Same testing basis as OK Compost INDUSTRIAL.

Why it’s worth knowing: European Bioplastics’ Seedling logo is widely visible on consumer products. Buyers seeing the Seedling can trust it represents OK Compost INDUSTRIAL or equivalent certification.

How the Tiers Relate

Important conceptual point: the tiers don’t form a strict hierarchy.

• A product can have OK Compost INDUSTRIAL without OK Compost HOME (most do).
• A product can have OK Compost HOME without all the others (rare; usually has INDUSTRIAL too).
• A product can have OK Bio-Based without any composting certification (biobased plastic that doesn’t compost).
• A product can have OK Marine Biodegradable without OK Compost (marine biodegradable doesn’t necessarily mean industrial-compost compatible).
• A product can have OK Soil Biodegradable without OK Compost (soil biodegradable in agricultural context might not pass compost facility testing).

For a B2B buyer, the implication is that no single certification covers all end-of-life pathways. Specifying the right combination requires understanding what disposal scenarios actually apply to your operation.

Verifying Claims

For products claiming OK Compost certification:

1. Check the certificate number: TÜV Austria maintains a searchable database of certified products. Each certification has a unique number.
2. Verify the certificate is current: certifications expire and require renewal. A 2018 certificate without renewal evidence is not currently valid.
3. Confirm the specific tier: ask which OK Compost mark exactly. The marks have different meanings.
4. Match the tier to your needs: industrial compost, home compost, marine, soil, biobased — each has different applicability.
5. Cross-reference with relevant ASTM/EN standards: a product claiming OK Compost INDUSTRIAL should also align with EN 13432; OK Compost HOME with relevant home-compost standards.

For B2B operators sourcing across the broader compostable foodware line — compostable food containers, compostable utensils, compostable cups and straws — single-supplier procurement maintains certification visibility across SKUs and reduces audit complexity.

Common Misconceptions

A few patterns worth flagging:

“OK Compost means everything composts”: depends on which mark. INDUSTRIAL means industrial conditions only. HOME means home compost. The marks aren’t interchangeable.

“Bio-based equals compostable”: false. Bio-based PE (bio-PE) is biobased but not compostable. Confirm specific compostability if that’s the requirement.

“Marine biodegradable means it’s safe to dump in the ocean”: no. Even marine-biodegradable products shouldn’t be disposed of in marine environments deliberately. The certification is about minimizing harm if accidental marine release occurs, not about authorizing intentional marine disposal.

“All the OK Compost tiers test the same thing”: false. Each tier tests different conditions and attributes. Read the specific certification carefully.

“A product certified five years ago is still certified”: not necessarily. Certifications expire. Check current status.

“OK Compost is the only credible compostability certification”: false. ASTM D6400 / BPI in the US are equally credible. ISO 17088 internationally. Different marks for different markets.

When You Need Each Tier

For B2B operators thinking about which certifications to specify:

OK Compost INDUSTRIAL: working baseline for any product marketed as compostable in European markets. Required for most foodservice applications. Equivalent to ASTM D6400 / BPI in US.

OK Compost HOME: useful for products marketed to consumers using home compost. Adds significant credibility for backyard-compost-friendly claims.

OK Bio-Based: relevant for marketing biobased content claims. Required for some procurement programs (government, defense, certain corporate sustainability programs).

OK Marine Biodegradable: relevant for products with marine disposal risk. Premium positioning for some consumer brands.

OK Soil Biodegradable: relevant for agricultural mulch films, garden products, products designed for soil end-of-life.

OK Water Biodegradable: relevant for freshwater-disposal-risk products.

Most foodservice operations need OK Compost INDUSTRIAL as their baseline. Premium positioning may add OK Compost HOME and/or OK Bio-Based. Specialty applications may add Marine, Soil, or Water.

The Geographic Picture

Europe: OK Compost INDUSTRIAL is the working default certification. Most consumer compostable products carry it. OK Compost HOME is increasingly common for home-compost-friendly products. The Seedling mark is widely visible.

North America: BPI (based on ASTM D6400) is the dominant equivalent to OK Compost INDUSTRIAL. Some US products carry OK Compost as well for European market access. OK Compost HOME is rarer in US products but growing.

Asia-Pacific: mix of ISO 17088, AS 4736 (Australia), and OK Compost certifications. Markets vary by country. Japan, Korea, Australia have growing compostable certification frameworks.

Latin America and Africa: OK Compost certifications are less common; markets often look to either US or European frameworks.

International supply chains: products selling across multiple regions often carry multiple certifications (OK Compost + BPI + AS 4736) to satisfy regional procurement requirements.

What’s Coming

Several developments in OK Compost certification worth watching:

Tightened standards: TÜV Austria periodically updates the OK Compost protocols. Recent updates have included tighter heavy metal limits, expanded ecotoxicity testing, and refined disintegration measurement.

New tier additions: TÜV occasionally adds new certifications for emerging needs. Marine and Soil tiers were added in recent decades; future additions may address other end-of-life scenarios.

Database transparency: TÜV Austria’s product database has expanded and become more searchable. Buyers can verify certifications more easily than in the past.

International alignment: ongoing work to align OK Compost with ISO 17088, ASTM D6400, and other regional standards. The standards landscape is becoming more harmonized over time.

PFAS-related additions: as PFAS bans become more widespread, OK Compost protocols increasingly require explicit PFAS-free testing. Some products that passed older protocols need re-certification under updated requirements.

For buyers, the trajectory points toward more rigorous certifications, more transparent verification, and more aligned international standards. The OK Compost framework will continue to be the working European baseline for compostability certification through the next decade.

A Working Buyer Checklist

For a procurement operator evaluating compostable supplier claims:

1. Identify required certifications based on markets and end-of-life pathways — INDUSTRIAL for most foodservice; HOME for home-compost-marketed products; Bio-Based for biobased content claims; specialty tiers as needed.

2. Verify certificate numbers in TÜV Austria’s database — each certification has a searchable number.

3. Confirm certifications are current — typically annual renewal.

4. Match certifications to the specific products, not the supplier broadly — a supplier may have some products certified and others not.

5. Document the certification details in your procurement file — supplier, product, certification type, certificate number, expiration date.

6. Cross-reference against US standards if relevant — BPI for ASTM D6400 equivalence in US markets.

7. Re-verify annually — certifications expire; products change; supplier mixes shift.

This due diligence prevents most procurement audit issues and customer-facing claims problems. For a single product line, the verification takes 10-30 minutes. For a full SKU portfolio, the process scales but remains manageable.

The Quiet Standard

The OK Compost certification family is one of the more rigorous compostability frameworks globally. The tiers are carefully designed, the testing is independent, the database is public, and the marks are widely recognized in European and international markets.

For B2B operators, foodservice managers, and product brands, the OK Compost framework provides the substrate for credible compostability claims. The marks aren’t marketing fluff; they’re the result of laboratory testing against defined criteria with ongoing renewal requirements.

The complexity of the tier structure can be confusing initially. Once the tiers are mapped to actual end-of-life pathways, the system becomes manageable. INDUSTRIAL for compost facility disposal. HOME for backyard compost. Bio-Based for renewable content. Marine, Soil, Water for environment-specific biodegradability. Each tier answers a different question.

For most foodservice and packaging applications, OK Compost INDUSTRIAL (or its US equivalent BPI) is the working baseline. Adding HOME certification adds credibility for consumer markets. Adding Bio-Based may be relevant for procurement programs. Specialty tiers fill specific use cases.

Get the right certifications for your operation. Verify them properly. Document the procurement decisions. The OK Compost framework does its work quietly underneath the visible packaging — turning vague compostability claims into testable, defensible, documented standards. That’s the working value of the certification structure, and it’s worth understanding tier by tier rather than treating “OK Compost” as a single undifferentiated mark.

The framework holds up. The certifications are real. The tier distinctions matter. Sourcing thoughtfully against this structure produces compostable programs that pass scrutiny and deliver the lifecycle benefits the products are designed to provide.