The Basics of Marine Biodegradation Standards: ASTM D7081, OK Marine, and What They Mean

A growing category of products — fishing gear, beach foodware, single-use plastics meant for outdoor use — get marketed with claims like “ocean-degradable,” “marine biodegradable,” or “breaks down in seawater.” These claims sound environmentally credible, but they’re often poorly substantiated. Most “biodegradable” plastics that work fine in commercial composting facilities don’t break down meaningfully in marine environments — they fragment into microplastics that persist for decades or centuries.

Marine biodegradation standards exist to differentiate products that actually break down in ocean conditions from those that just disintegrate visually. The two main standards are ASTM D7081 (US) and OK Marine (European/global). For B2B buyers, brand managers, and procurement teams, understanding what these certifications require is essential for credibly making marine biodegradation claims.

This article walks through what the standards test, what passes and fails, and how to evaluate marine biodegradation claims.

Why marine biodegradation is different

Marine environments differ from terrestrial composting in important ways:

Temperature: ocean temperatures range from 28°F (Arctic) to 86°F (tropical), with most waters at 50-75°F. Commercial composting facilities operate at 130-150°F (54-65°C), which is roughly 50°F warmer than ocean water. This temperature gap dramatically affects biodegradation rates.

Oxygen: ocean surfaces are well-oxygenated, but deeper waters and seabed sediments are increasingly oxygen-limited. Different microbial communities operate at different oxygen levels.

Salinity: seawater is 3-3.5% salt by weight. Salt-tolerant microbes are the only ones that work; many soil-pile decomposers don’t function in salt water.

Microbial communities: marine microbiomes are different from terrestrial ones. The microbes that break down certain materials in compost don’t exist in significant numbers in seawater.

UV exposure: floating debris at the ocean surface is exposed to intense UV. Some materials photodegrade (break down due to UV) faster than they biodegrade.

A “compostable” product that fully breaks down in 60-90 days in a commercial compost facility might persist for 10-50+ years in marine environments. The standards that matter for ocean applications are specifically marine-validated.

ASTM D7081: the US standard

ASTM D7081 (Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment) is the dominant US standard for marine biodegradation claims. Key requirements:

1. Disintegration test (90-day): the material must visibly disintegrate within 90 days under marine conditions.
2. Biodegradation test (180-day): at least 60% of the material’s carbon must convert to CO2 within 180 days under marine conditions.
3. Aquatic toxicity testing: the decomposition byproducts must not harm aquatic life.
4. Heavy metals testing: the material must not contain heavy metals above specific thresholds.

The testing conditions:

• Water temperature: typically 30°C (86°F), simulating tropical ocean conditions.
• Sediment exposure: the material is partially buried in marine sediment, simulating actual deposition.
• Oxygen conditions: typically aerobic but with realistic seawater oxygen levels.
• Microbial communities: natural marine microbes from collected seawater.

ASTM D7081 is intentionally rigorous. Products that pass have demonstrated real marine-environment biodegradation, not just laboratory plastic decomposition.

OK Marine: the European/global standard

OK Marine certification is issued by TÜV Austria (the same organization that issues OK Compost for industrial composting and OK Compost Home for backyard composting). It’s based on ASTM D7081 but adds some additional requirements:

1. All ASTM D7081 criteria above.
2. Stricter biodegradation timeline: 90% biodegradation in 365 days (vs. 60% in 180 days for ASTM D7081).
3. Multiple temperature conditions: tested across temperature ranges to verify performance in non-tropical waters.
4. Lower toxicity thresholds: stricter aquatic toxicity limits.

OK Marine is generally considered more rigorous than ASTM D7081 because of the higher biodegradation threshold and temperature variation testing. Products with OK Marine certification have demonstrated marine biodegradation across a broader range of real-world conditions.

What passes (and what doesn’t)

Materials that have been tested and pass ASTM D7081 or OK Marine:

PHA (polyhydroxyalkanoates): the strongest marine biodegradation performer. PHA is produced by microorganisms (some are produced industrially using bacteria; others are produced by extracting from natural sources). PHA breaks down in marine environments because the same microbial pathways that produce it can also consume it. Some PHA products are certified to break down in months in seawater.

Some pulp/paper products: uncoated paper, kraft paper, and some untreated paper fibers can biodegrade in marine environments at slow but acceptable rates. Coated paper (with PE or even PLA linings) generally doesn’t pass marine standards.

Some pure natural fibers: wool, untreated cotton, hemp fiber. These biodegrade in marine environments at acceptable rates for some applications.

Materials that have NOT been able to pass marine biodegradation standards:

PLA: despite being compostable in industrial facilities, PLA does not biodegrade meaningfully in seawater. Standard PLA can persist for decades or centuries in marine environments. This is a major reason PLA-based products aren’t suitable for ocean applications.

Conventional plastics (PET, HDPE, PP, PVC): essentially zero marine biodegradation. They photodegrade and fragment into microplastics over decades.

Most “biodegradable” plastics: despite the marketing, most products labeled “biodegradable” without specific marine certification don’t actually break down in marine environments. They’re optimized for compost or soil, not seawater.

Bagasse and palm leaf (mostly): the natural fiber components biodegrade slowly in marine environments, but bagasse products often have additives (binders, coatings) that don’t. Pure unmodified bagasse can biodegrade in seawater but slowly.

Real-world products with marine certification

Products that legitimately carry marine biodegradation certification:

Fishing gear: some fishing line, lobster trap escape vents, and bait packaging materials are PHA-based and certified for marine biodegradation. This is a meaningful category because lost fishing gear is a major source of marine plastic pollution.

Single-use beach products: some compostable straws (PHA-based) and beach picnic items are marine-certified. The use case is honest — these items can be lost to the ocean and break down rather than persisting.

Aquaculture products: some net materials, feed packaging, and aquaculture-related items are marine-certified.

Outdoor packaging: some packaging products designed for outdoor sports, beach use, or marine activities are marine-certified.

Hygiene products: some marine-certified PHA-based diaper materials and feminine hygiene products are emerging in some markets, though these are still niche.

What “marine degradable” doesn’t mean

A few common misunderstandings:

“Marine biodegradable” doesn’t mean “you can throw it in the ocean.” Even certified marine biodegradable products should be properly disposed of. The certification means it breaks down if accidentally lost; it doesn’t mean it’s appropriate to deliberately dispose of in the ocean.

It doesn’t mean “all-environment biodegradable.” A product certified for marine biodegradation may still need commercial composting to break down in terrestrial conditions. Marine and compost biodegradation are different.

It doesn’t mean “no microplastics.” Some marine-certified products break down into smaller pieces before fully mineralizing. The intermediate stage may still produce small particles before complete biodegradation occurs.

It doesn’t mean “fast.” “Marine biodegradable” can mean breakdown over months for the best products, but more commonly means breakdown over 1-3 years. This is still much faster than conventional plastic (decades to centuries), but it’s not instant.

Cost and availability

Marine-biodegradable products are significantly more expensive than alternatives:

• PHA products: $4-$8 per kg for raw material, vs. $1-$2 per kg for PLA, vs. $1-$1.50 per kg for conventional plastic. Finished products see 3-8x cost premium over equivalent conventional plastics.

• Limited supplier base: only a handful of PHA producers operate at commercial scale (Danimer Scientific, RWDC, NaturePlast, Mango Materials, others). Supply chains are tight.

• Certification cost: marine biodegradation certification testing is more expensive than commercial composting certification ($30,000-$60,000+ for a product to be certified).

For B2B buyers, marine-certified products are niche. They make sense in specific applications — marine industries, beach foodservice, outdoor recreation — where the use case justifies the cost premium and the environmental risk of marine debris is real.

For general foodservice operations, marine certification is rarely the right priority. Compost-certified products (BPI for industrial; OK Compost Home for backyard) match the more common disposal pathway.

How to evaluate marine biodegradation claims

For a B2B procurement team evaluating supplier marine biodegradation claims:

1. Ask for the specific standard. ASTM D7081, OK Marine, or another? Generic “marine biodegradable” without a standard isn’t enough.

2. Ask for the certification documentation. PDF certificate from TÜV Austria, ASTM-accredited lab, or similar.

3. Ask which environmental conditions were tested. Tropical surface? Cold deep water? Sediment exposure? The conditions affect what the certification actually covers.

4. Verify the certification is for the finished product. A supplier might have PHA resin certified for marine biodegradation but added coatings, dyes, or fillers that haven’t been re-certified.

5. Check for greenwashing flags. “Eco-friendly,” “ocean-safe,” and similar vague claims without specific standards are usually marketing rather than substance.

A regulatory context

Marine biodegradation standards interact with several regulatory frameworks:

California Marine Plastics legislation (multiple state laws 2018-2025): California has been particularly active in regulating marine debris. Some applications (fishing gear, plastic film) face mandatory biodegradation or alternative-material requirements.

EU Plastics Directive and Marine Strategy Framework Directive: the EU has both general marine pollution rules and specific plastic-product regulations. Marine biodegradation standards are increasingly referenced in these frameworks.

Federal Marine Debris Act (US): sets the broader policy framework but doesn’t currently mandate specific biodegradation standards.

International IMO standards: the International Maritime Organization is developing standards for marine biodegradation of fishing gear that may become global requirements.

The regulatory direction is clearly toward more accountability for marine debris and more requirements for biodegradable alternatives in high-loss applications. Products that aren’t actually marine biodegradable but are marketed that way face increasing scrutiny.

The FTC Green Guides perspective

The US FTC Green Guides specifically address marine biodegradation claims:

Required: specific evidence of biodegradation in marine environments. Generic “biodegradable” claims that aren’t backed by marine-specific testing are misleading.

Required: time frame specification. A product that “biodegrades” over 10 years is not equivalent to one that biodegrades in 6 months. Claims should specify timeframe.

Required: testing methodology disclosure. The standard used (ASTM D7081, OK Marine, etc.) should be available on request.

Prohibited: “ocean-safe” or “marine-friendly” claims that aren’t substantiated by specific testing.

The FTC has taken enforcement action against multiple companies for misleading marine biodegradation claims. The standards exist; the regulators expect them to be honored.

A working application

Consider a fishing tackle company developing biodegradable lure components. The procurement and certification path:

1. Material selection: PHA-based bioplastic from a certified supplier (e.g., Danimer Scientific’s Nodax line).
2. Product engineering: the lure component is molded from PHA with no additives that would invalidate biodegradation.
3. Testing: the finished component is tested for marine biodegradation under ASTM D7081 conditions. Testing fee: ~$40,000-$60,000.
4. Certification issuance: assuming the test passes, the company can claim ASTM D7081-certified marine biodegradation.
5. Marketing claim: “Made from PHA, certified to biodegrade in marine environments under ASTM D7081 standards within 180 days.” Specific, time-bound, standard-referenced.
6. Cost premium: the PHA-based component costs roughly 3-5x equivalent conventional plastic. Premium is absorbable in specialty fishing tackle market where buyers value performance and increasingly value environmental claims.

This is a credible marine biodegradation positioning. The claim is specific, the standard is named, the timeframe is bounded, and the cost premium is real but workable.

What’s next for marine biodegradation

The category is evolving:

More PHA producers entering the market. Several startups and incumbents are scaling PHA production over 2025-2030, which should drive prices down and availability up.

Newer materials. Emerging materials like carbon-negative bioplastic from CO2 (using bacterial fermentation), seaweed-based plastics, and chitin-based plastics may add to the marine-biodegradable portfolio.

Regulatory pressure. EU and US regulatory frameworks are tightening on marine debris, which should drive more demand for marine-certified products.

Standards evolution. ASTM and OK Marine are likely to update their criteria over time as understanding of marine ecosystems improves.

Application expansion. Currently niche applications (fishing gear, beach products) may expand to broader categories like outdoor furniture, marine paints, and recreational products.

Practical guidance

For a B2B operator considering marine biodegradation claims:

1. Verify the use case justifies the cost. A 3-5x premium over conventional plastic is real. Make sure your product genuinely faces marine debris risk that warrants the premium.

2. Source from credible PHA or natural fiber suppliers. Established manufacturers with documented certifications.

3. Test in real conditions. Lab certification is good; field testing in actual marine conditions is better. Some industry-led pilot programs (fishing gear, beach foodware) coordinate field testing.

4. Communicate honestly. Specific standards, specific timeframes, specific conditions. Avoid vague “ocean-friendly” claims.

5. Watch the regulatory landscape. Marine biodegradation requirements are tightening. Get ahead of regulation rather than reacting to it.

Comparison table: marine vs. compost biodegradation

The two pathways are largely independent. A product certified for one isn’t necessarily certified for the other, and the engineering required for both can be different. Some PHA-based products are dual-certified for both marine and industrial composting; this is unusual but available for specialty applications.

A note on home-pile alternatives

For products designed to potentially end up in home compost piles (rather than industrial facilities or marine environments), the relevant standard is OK Compost Home (different from OK Marine). OK Compost Home tests biodegradation at ambient temperatures (20-30°C / 68-86°F), simulating backyard piles. Different microbial conditions; different materials pass; different test parameters.

OK Compost Home is generally considered more rigorous than OK Compost Industrial because of the lower temperature requirement. Products that pass OK Compost Home usually pass OK Compost Industrial as well, but not vice versa.

For B2B buyers considering products with multiple potential disposal pathways (a consumer might compost in backyard, send to commercial facility, or accidentally throw outside), products certified across multiple standards (OK Compost Home + OK Compost Industrial + OK Marine, where applicable) provide the strongest claim.

Bottom line

Marine biodegradation standards (ASTM D7081, OK Marine, others) are the credible technical basis for products that claim to break down in ocean environments. The standards are rigorous; certification is expensive; the materials that pass are still relatively few (PHA dominates).

For most B2B foodservice and consumer product categories, marine biodegradation isn’t the right priority — products that go to landfill or commercial compost are better optimized for those pathways than for marine pathways. Marine certification matters for products with real marine exposure risk: fishing gear, beach products, aquaculture-related items, outdoor recreation products that may be lost.

Where marine certification matters, it should be specific (named standard, named conditions, named timeframe). Vague “ocean-safe” claims without certification are marketing rather than substance, and regulators are increasingly active in distinguishing the two.

The category is small but growing. As materials science improves and regulatory pressure tightens, marine biodegradation is likely to expand from a specialty niche to a more mainstream concern. For B2B buyers, understanding the basics now positions the operation for the regulatory environment of 2026-2030 and beyond.

For B2B sourcing, see our compostable supplies catalog or compostable bags catalog.

Background on the underlying standards: ASTM D6400 defines the U.S. industrial-compost performance bar, EN 13432 harmonises the EU equivalent, and the FTC Green Guides govern how “compostable” can be marketed on packaging in the United States.