EN 13432, ASTM D6400 and Biodegradability Claims: The 4 Criteria That Decide What Additives a Compostable Plastic May Contain

EN 13432 sets 4 pass criteria for an industrially compostable plastic, and 2 of them are numbers: the material must biodegrade by at least 90 % within 6 months and leave under 10 % of its original mass as residue after 3 months of pilot composting. Both numbers apply to the finished article and not to the base polymer, so which of the additives in the recipe can that article afford to carry?

The 4 criteria are chemical characterisation, biodegradation, disintegration and ecotoxicity, and each one removes a different group of ingredients from a compostable compound. Chemical characterisation excludes metal-bearing additives and any constituent nobody has tested. Biodegradation, measured under EN 14046, excludes non-biodegradable organics such as hindered amine light stabilizers and fluoropolymer processing aids. Disintegration, measured under EN 14045 in a pilot composting test, counts inert mineral filler in full as residue. Ecotoxicity tests the whole article on the composting process and on plant growth in the compost that comes out.

This page sets out what EN 13432 is and is not, the 4 criteria and the test standard behind each, which of 15 additive families each criterion makes required, conditional or excluded, how ASTM D6400 changes the paperwork rather than the recipe, how compostable differs from biodegradable and from oxo-degradable, what a claim may legally say in the European Union and the United States, and how a certificate sits beside the PPWR, Regulation (EU) No 10/2011 and the chemical restrictions. It is a technical reference for formulators, compounders and converters, not legal advice. EN 13432:2000 is a paywalled CEN standard, and its text is not reproduced here.

Table T1: The 4 EN 13432 criteria at a glance

EN 13432:2000 is a CEN standard, not EU law. The four characteristics and the two numeric pass values come from the European Bioplastics background paper on EN 13432. The heavy-metal maxima and the per-constituent de-minimis threshold are in the standard and scheme texts, which are paywalled and are not reproduced on this page.

What Is EN 13432 and What Does It Certify?#

EN 13432:2000 is the European standard "Packaging: Requirements for packaging recoverable through composting and biodegradation: Test scheme and evaluation criteria for the final acceptance of packaging", and it certifies that a packaging item breaks down in an industrial composting plant without harming the compost that comes out. Industrial composting is not a garden heap, so what conditions does the standard assume? Industrial composting heaps run at 50 to 60 °C, and that thermal environment is the one all 4 criteria are measured in.

What the certificate covers is conformity with that test scheme, nothing wider. CEN writes the standard; certification against it is issued by schemes, and 3 of them carry the market: the OK compost programme of TÜV Austria, DIN CERTCO in Germany and BPI in the United States. The four characteristics and the two numeric pass values quoted throughout this page come from the European Bioplastics background paper on the standard, the association that publishes the bioplastics capacity data with the nova-Institute. The standard evaluates a packaging item. It does not authorise a substance, and nothing in it clears an additive for use.

Which packaging does EN 13432 cover, and which parts of it#

EN 13432's criteria attach to the finished packaging item and to every component and constituent inside it, so a compostable film is judged together with its printing ink, its label adhesive, its colour masterbatch and every additive in the compound. The certifier's requirement note behind the standard states the rule in one line: a packaging may be deemed compostable only if all the constituents and components of the packaging are compostable. Three levels therefore carry the obligation:

• The packaging item as it is placed on the market, at its real wall thickness and in its real format
• Each component of that item, which for a film pouch means the film, the label, the closure and the printed ink layer
• Each constituent of each component, which means the polymer, the colorant, the nucleator, the plasticizer, the chain extender, the slip agent and the filler

Certification schemes soften the third level with a de-minimis rule for any single untested constituent plus a cap on the sum of constituents not tested for biodegradability, but both figures sit in paywalled scheme documents and neither is published here. Constituent-level certification is not theory: DIN CERTCO certifies printing inks, inorganic pigments, organic dyes, colour masterbatch based on biodegradable materials, and biodegradable additives against DIN EN 13432 in their own right. The same logic reaches the whole package for additives for food packaging, which clears the compostability criteria and the food-contact migration limits at once. Under Article 9(1) of the PPWR the commercial scope is narrow: permeable tea, coffee and other beverage bags, soft single-serve units, and sticky fruit and vegetable labels.

What is the difference between EN 13432 and EN 14995?#

EN 13432 applies to packaging and EN 14995 applies the same four criteria to plastics that are not packaging, such as cutlery, tableware and agricultural items, so a formulator who has cleared one has cleared the technical content of the other. The split is one of scope, not of chemistry: both standards sit in the same family as the test methods EN 14045 and EN 14046, and both read the constituent rule the same way. What differs is the certificate a buyer asks for, because a packaging buyer and a tableware buyer are served by different scheme annexes.

Is EN 13432 a law or a voluntary standard?#

EN 13432 is a voluntary CEN standard and not a law, but two legal routes make it a commercial requirement: the PPWR obliges four packaging types to be industrially compostable by 12 February 2028, and Californian law allows the word "compostable" on a plastic product only when the ASTM specification is met. Regulation (EU) 2025/40, the Packaging and Packaging Waste Regulation, applies from 12 August 2026. Its Article 9(1) sets the 12 February 2028 deadline for the four packaging types named above, requires home compostability where a Member State requires it, and lets Member States extend the duty to non-permeable beverage capsules and to very lightweight and lightweight carrier bags.

Article 9(3) runs the other way for everything else: all other packaging, including packaging made of biodegradable polymers, must be designed for material recycling by the same date. The regulation also required the Commission to request harmonised compostability standards by 12 February 2026. Whether that request produced a mandate is not recorded in our source library, so this page states the duty and its date and nothing about the outcome. On the American side, California Public Resources Code 42357 makes the ASTM specification the condition for using the word "compostable" on a plastic product at all.

The 4 EN 13432 Criteria, Their Test Standards and What Each One Does to an Additive#

The 4 EN 13432 criteria are chemical characterisation, biodegradation, disintegration and ecotoxicity, and each one removes a different group of additives from a compostable formulation. That order is the order the test scheme runs and the order a formulator meets them: chemical characterisation first, because it is a desk check on the recipe and the only criterion a formulation can fail on paper, then biodegradation, then disintegration, then ecotoxicity on the compost that results.

Read as a package, the four criteria reach only a part of the 43 families of plastic additives, and they reach each one differently. A nucleating agent is usually necessary to make a bio-polyester processable at all, a hydrolysis stabilizer works directly against criterion 2, and a mineral filler is chemically harmless while still consuming criterion 3's residue budget. That asymmetry, not a blanket exclusion, is what a compostable formulation is designed around.

1. Chemical characterisation: heavy metals, fluorine and the constituent rule#

Chemical characterisation is the first EN 13432 criterion and the only one a formulation can fail on paper: it requires the identity of every constituent to be declared and the regulated metals and fluorine to stay below the maxima set in the standard. The standard sets a maximum concentration for each of eleven elements, namely zinc, copper, nickel, cadmium, lead, mercury, chromium, molybdenum, selenium, arsenic and fluorine, and the certification scheme sets the de-minimis rule for an untested constituent. Both figures sit in paywalled texts and are not reproduced here.

This criterion has two independent teeth, and the second one is the reason this page exists. A metal above its maximum fails the item outright, which is a familiar problem with a familiar answer. A constituent that nobody has tested for biodegradability also fails the item, unless it stays under the scheme's de-minimis threshold, and that tooth catches speciality additives dosed below 1 wt%, where no supplier datasheet mentions composting at all. The plasticizer load in a PLA film is the largest single organic constituent after the polymer, and plasticizers for PLA are compared on their own page.

For scale, from a different instrument with a different purpose, Annex II of Regulation (EU) No 10/2011 sets metal migration limits in food of 1 mg/kg for aluminium and for barium, 0.05 mg/kg for cobalt, 5 mg/kg for copper, 48 mg/kg for iron, 0.6 mg/kg for lithium and for manganese, 0.02 mg/kg for nickel, 5 mg/kg for zinc, and 0.05 mg/kg for the sum of europium, gadolinium, lanthanum and terbium. Those values protect food and EN 13432's maxima protect compost, so neither set reads across to the other. Article 5(4) of the PPWR reaches the same metals a third time, capping the sum of lead, cadmium, mercury and hexavalent chromium at 100 mg/kg of the packaging or packaging component.

Table T2: Where the regulated elements come from in a compostable formulation

The EN 13432 maximum for each element is in the standard text and is not reproduced here. The EU limits in column 4 are different instruments with different purposes, given for scale only: EU 10/2011 Annex II limits migration into food, REACH Annex XVII limits content in the article, and PPWR Article 5(4) limits a four-metal sum in packaging. Our source library holds no mercury-, molybdenum-, selenium- or arsenic-containing plastic additive.

Which additives carry the regulated metals into a compostable plastic?#

Three additive groups carry the regulated metals into a compostable plastic: inorganic pigments containing cadmium, lead or chromium, metal soaps such as zinc stearate used as lubricants and acid scavengers, and catalyst or pro-oxidant residues including the tin catalyst carried over from PLA polymerisation. Each reaches the compound by a different route, which is why one screening question does not catch all three:

• Inorganic pigments, where the metal is the chromophore itself and the dose is set by the colour target, not by a performance minimum
• Metal soaps and stearates, where the metal is the counter-ion of a fatty acid and the function sits in the acid, which makes substitution possible
• Catalyst and pro-oxidant residues, where nobody added the metal deliberately to the compound at all, because it arrived with the resin or with a masterbatch

The metal soaps are where the substitution route is real, and the calcium, zinc and magnesium grades are compared on metal stearates. Calcium stearate at 1 wt% is a documented PLA demoulding level, and calcium carries no entry on the standard's eleven-element list while zinc does, so a calcium-based soap at a similar dose removes a metal load without removing the function. Colour has the same move by a different mechanism: organic dyes and metal-free pigments are certified as separate product groups by DIN CERTCO, and the cadmium-free and lead-free complex inorganic pigments for plastics are the surviving options where an inorganic is unavoidable. Pro-oxidant stearates of iron, manganese and cobalt are excluded in all three cases. The pigment levels in our source library, from the ECHA use mapping, are general-plastics figures of mostly 2 wt% for organic pigments and 5 wt% for titanium dioxide and complex inorganic pigments, not compostable-grade figures.

2. Biodegradation: at least 90 % within 6 months#

The second EN 13432 criterion requires at least 90 % of the material's organic carbon to be converted to carbon dioxide by micro-organisms within 6 months, measured under EN 14046. The percentage is a percentage of organic carbon, not of mass and not of the polymer alone, and the measurement runs at the 50 to 60 °C of an industrial heap. PLA shows how tight that window is: about half of a PLA article decomposes in 60 days at 58 °C, full degradation needs temperatures above 60 °C, and PLA's glass transition of 60 to 65 °C and melting range of 130 to 180 °C sit immediately above the heap.

Because the criterion counts organic carbon, every organic additive is part of the mass being measured. Four classes recorded in our source library as non-biodegradable organics therefore need limiting: hindered amine light stabilizers, phosphite antioxidants, silicone slip agents and fluoropolymer processing aids. None of the four is forbidden by the standard as a named substance; each is simply organic carbon that does not convert.

One family conflicts with this criterion by design, because a hydrolysis stabilizer exists to stop the hydrolytic chain scission that EN 14046 measures. Pfaendner's group at Fraunhofer LBF reported an aziridine-based hydrolysis stabilizer that held PLA's molecular-weight loss to about 10 % after 850 hours of hydrolytic ageing and up to 20 % after 1,200 hours (Hallstein, Metzsch-Zilligen and Pfaendner, Polymers, 2024), exactly the durability a compostable article must not have. The same work records that polycarbodiimide and aziridine stabilizers suppress PLA crystallinity below 5 %, and Lanxess reports that Stabaxol P 110 cuts melt volume rate by 20 to 30 % against once-extruded unstabilised PLA. A technically excellent additive can be the wrong additive, and this is the clearest case of it on the page.

Do the additives have to biodegrade as well as the polymer?#

Yes: EN 13432 treats a packaging item as compostable only when all of its constituents are, so every additive in the compound either carries laboratory biodegradability evidence of its own or has to stay under the certification scheme's de-minimis threshold for an untested constituent. That is why additives are certified separately at all. DIN CERTCO's product groups for additive certification against DIN EN 13432 are printing inks, inorganic pigments, organic dyes, colour masterbatch based on biodegradable materials and biodegradable additives, and the body states that where additives are certified, final-product makers can dispense with possible further test procedures. The de-minimis threshold itself sits in a scheme document this page does not reproduce.

The US Composting Council states the same rule for the American standards: meeting ASTM D6400 or D6868 requires individual ingredients to be tested for biodegradability, and then the finished article is tested as well. Certification always attaches to a named grade from a named supplier, never to a chemistry in the abstract, which is why a public certificate register exists and why "certified compostable additive" means nothing without the grade name attached.

3. Disintegration: under 10 % residue after 3 months in a pilot composting test#

The third EN 13432 criterion limits the residue that survives a 3-month pilot composting test to under 10 % of the test item's original mass, measured under EN 14045, which the industry also quotes as 90 % disintegration within 12 weeks. The percentage is a percentage of mass, which makes this the one criterion a chemically innocent ingredient can fail. An inert mineral filler does not biodegrade and does not disappear, so it counts in full against the 10 %, and a compostable compound therefore has a filler budget expressed in mass that is consumed before any question of toxicity or migration arises.

Filler chemistry splits the verdict. A cellulose-based filler contributes carbon that is itself biodegradable: Lang and colleagues reported in Polymers in 2022 that 4 % microcrystalline cellulose in a PBAT and thermoplastic-starch film gave the optimum mechanical result, at 5.08 MPa tensile strength and 230 % elongation. A mineral nanoclay sits at the other end, and the limit that applies to it is a food-contact one rather than a composting one: organoclay FCM 1075 is capped at a maximum of 4.0 % w/w in PLA under Regulation (EU) No 10/2011 for long-term water storage at ambient temperature or below. Wall thickness works the same way as filler loading, since anything thicker or tougher disintegrates more slowly, so impact modifiers and reinforcing fillers are constrained here even when their chemistry is acceptable. The methods behind every criterion on this page are indexed under testing plastic additives.

4. Ecotoxicity: no negative effect on composting and no harm to plant growth#

The fourth EN 13432 criterion has two halves: the material must not disturb the composting process itself, and the compost it leaves behind must not be ecotoxic to plants. Both halves are measured on the finished article rather than on an additive in isolation, and they divide the way the standard's own characteristic wording divides:

• The process effect, meaning no negative effect on composting, which is about what the material does to the heap and the micro-organisms working in it
• The compost-quality effect, meaning heavy metals below the set maxima and no ecotoxic effect on plants, which is about what the heap hands on to the soil

Three additive groups reach this criterion. Antimicrobials and other biocides reach it by design, because inhibiting microbial growth is their function and composting is microbial. Metal-bearing additives reach it through the compost's metal load, which is criterion 1 arriving at a second checkpoint. Anything carrying a harmonised aquatic or soil hazard classification reaches it by classification alone, before any test is run. DIN CERTCO, which certifies additives against DIN EN 13432 in their own right, runs plant compatibility, earthworm toxicity and nitrification tests alongside chemical characterisation, laboratory biodegradability and an infrared transmission spectrum. Those three ecotoxicity tests belong to the certifier's scheme rather than to the standard's criteria, and no germination index, plant-growth pass percentage or earthworm mortality threshold is published here, because none is in our source library.

EN 13432 vs ASTM D6400: What Changes in the Formulation#

ASTM D6400 is the US specification for labelling plastics designed to be aerobically composted in municipal or industrial facilities, and for a formulator it changes the paperwork and the certifier far more than it changes the recipe. Three things follow, in order. First, both standards run the same four-area logic of chemical characterisation, biodegradation, disintegration and compost quality, so the evidence file has the same shape on both sides of the Atlantic. Second, both apply the constituent rule, which is why the additive question is identical: the US Composting Council states that meeting ASTM D6400 or D6868 requires individual ingredients to be tested for biodegradability and the finished article to be tested as well. Third, the numbers differ, and this page publishes only the numbers it has verified, the EN 13432 values of at least 90 % biodegradation in 6 months and under 10 % residue in 3 months.

ASTM D6400's biodegradation percentage and its maximum time frame are set in the ASTM text and are not reproduced here. Nor is an edition year: five of them circulate across the public results for this standard, so this page writes "the current edition". ASTM D6400 is a labelling specification rather than a certification mark, and BPI states that it uses ASTM D6400 as the base standard for assessment of all items going through its certification process, with optional assessment to ASTM D6868 for plastic coatings on a substrate. One further ASTM standard is routinely confused with these: ASTM D6866 measures biologically derived carbon content by radiocarbon analysis using accelerator mass spectrometry, and it says nothing about biodegradation.

Table T3: EN 13432, ASTM D6400 and EN 14995 side by side

The "not reproduced here" cells are deliberate. The ASTM D6400 pass values and the EN 13432 element maxima sit in paywalled standard texts this reference has not read. Competitor pages quote figures for them; this page does not repeat figures it has not verified against the source.

Which other compostability standards exist, and what they cover#

Eleven standards sit around EN 13432, and only four of them test industrial compostability: the rest test home composting, soil, fresh water, open-air oxidation or bio-based carbon content, and none of those is interchangeable with EN 13432. Grouping them by what they actually measure is the only way to use them safely, because the home-composting, soil, fresh-water and bio-based-content standards are all quoted in marketing as though they were compostability standards. Biodegradable mulch film has its own page on this site, and its standard, EN 17033, appears below with its scope and without a criterion.

Table T4: The standards landscape around EN 13432

Biodegradability depends on the chemical structure of the polymer, not on whether its carbon came from a plant. ASTM D6866 measures the second thing and is often quoted as if it measured the first.

Which Additives Fit a Compostable Formulation, and Which Do Not#

A compostable formulation splits its additives three ways: nucleating agents, chain extenders and plasticizers are needed to make bio-polyesters processable, fillers and colorants are conditional on what they are made of, and hydrolysis stabilizers, hindered amine light stabilizers, phosphites, silicone slip agents and fluoropolymer processing aids are excluded by one criterion or another. The split is not a preference list. Each verdict traces back to a criterion from the section above, and the criterion names the test that would catch it.

PLA is the polymer where all three directions meet, because it needs nucleation to crystallise, chain extension to hold molecular weight through film blowing and plasticizing to reach useful elongation, and the full package for additives for PLA covers nucleation, plasticizing, chain extension and impact at once. The polymers behind the other compostable formulations, PBAT, PBS, PHA and starch blends, have their own additive guide on this site. Table T5 sets each family against the criterion it threatens, the dosage level recorded in our source library and the resulting verdict.

Table T5: Additive family against the criterion at risk, typical level and verdict for a compostable grade

Every value in this table is repeated from the criteria sections above or from the per-family pages linked in column 2. No dosage in this table is a compostable-grade recommendation: each one is the level recorded for that additive in its normal use, given so a formulator can see how much constituent mass the function actually costs.

Qualify an additive for a compostable grade in 5 steps: list every constituent, total the regulated metals, collect biodegradability evidence for each organic ingredient, test the finished article, then file the declaration with the food-contact and PPWR documentation.

1. List every constituent of the finished article, not only the polymer: resin, masterbatch carrier, pigment, nucleator, plasticizer, chain extender, slip agent, filler, printing ink and label adhesive.
2. Total the regulated metals across all of them and check the sum against the standard's element maxima, remembering that a colour masterbatch and a metal soap draw on the same budget.
3. Collect laboratory biodegradability evidence for every organic constituent, or keep that constituent under the certification scheme's de-minimis threshold for an untested ingredient.
4. Test disintegration, biodegradation and plant growth on the finished article at its real wall thickness, not on the additive alone.
5. File the certifier's constituent declaration together with the food-contact and PPWR documentation for the same packaging, because the three evidence sets are read together.

Steps 2 and 3 settle a formulation before any sample goes to a laboratory, since both are desk checks and both are cheap. The CAS number and regulatory status of every substance named above is in the plastic additives database.

Compostable, Biodegradable and Oxo-Degradable Are Three Different Things#

Compostable means a material passes the 4 EN 13432 criteria in an industrial composting plant, biodegradable means only that micro-organisms can break it down in an unstated environment over an unstated time, and oxo-degradable means the material carries a pro-oxidant additive that fragments it, which is why products made from it have been banned in the EU since 3 July 2021. The three words are not degrees of the same property. "Biodegradable" on its own is not a specification: it becomes one only when the receiving environment and the timeframe are stated, which is what the Commission's claims framework requires. Biodegradability depends on the chemical structure of the material and not on the origin of its carbon, which is why a bio-based polymer can be entirely non-biodegradable.

How does a buyer tell them apart on a product? By a conformity mark from a named scheme on a named grade, and by nothing else. Three marks carry the industrial-composting claim: the Seedling logo named in the European Bioplastics background paper on EN 13432, OK compost from TÜV Austria, and BPI certification in the United States. A home-compostable claim is a separate standard and a separate mark, and the PPWR defines compostable packaging and home compostable packaging separately in its Article 3. The oxo, enzymatic and pro-degradant types behind the third term are compared, with their evidence, on biodegradation additives for plastics.

Why oxo-degradable additives fail every compostability standard#

Oxo-degradable additives are pro-oxidant iron, manganese or cobalt salts that accelerate photo-oxidation through hydroperoxide homolysis, which is the exact opposite of what a stabilizer does, and they fragment a polyolefin rather than mineralising it. Activity ranks iron below manganese below cobalt, and Konduri and colleagues measured in 2011 how far the mechanism reaches: after ultraviolet exposure followed by Aspergillus oryzae, tensile strength fell by 51 % for manganese stearate, 45 % for titanium, 40 % for iron and 39 % for cobalt stearate, with manganese stearate also cutting elongation by 62 %. Loss of tensile strength is fragmentation, not mineralisation.

Three pieces of evidence close the question, in order of directness. First, the timescale: EN 13432 asks for 90 % biodegradation in 6 months, and the best published soil result for LDPE with manganese stearate is 91 % after 753 days, while Sciscione, Hailes and Miodownik at University College London reviewed the field in Royal Society Open Science in 2023 and found most pro-oxidant plastics reach only 5 to 60 % biodegradation, short of PAS 9017. Second, the direct test: Vaverková and colleagues found in 2014 that HDPE bags with TDPA and polypropylene with d2w showed no degradation after 12 weeks in a municipal composting facility, while certified-compostable bags decomposed there. Third, COM(2018) 35, the Commission's 2018 report on oxo-degradable plastic, found no conclusive evidence of full biodegradation in any open environment and concluded that the material is not suitable for composting or anaerobic digestion.

Article 5 of Directive (EU) 2019/904 prohibits placing products made from oxo-degradable plastic on the market, applicable since 3 July 2021, and Article 3(3) defines the material by its additive: plastic containing additives which, through oxidation, lead to fragmentation into micro-fragments or to chemical decomposition. The General Court dismissed Symphony Environmental's damages action in Symphony Environmental v Parliament and Others (T-745/20, 31 January 2024) and held that the ban lawfully makes no distinction between oxo-degradable and so-called "oxo-biodegradable" plastic. The jurisdiction-by-jurisdiction picture is on oxo-degradable plastic bans, and the chemistry on oxo-degradable additives.

Do enzymatic additives make a plastic compostable?#

Enzymatic additives work only in polyesters: an engineered PLA hydrolase at 0.02 % by weight of the film let a PLA article disintegrate under home-compost conditions within 20 to 24 weeks, while polyolefins do not associate with enzymes at all. Guicherd and colleagues reported that engineered hydrolase in Nature in 2024 for Carbios, formulated into a polycaprolactone masterbatch at 70 °C and then compounded into PLA at 160 °C, the processing route that keeps the enzyme active through extrusion. DelRe and colleagues in Ting Xu's group at the University of California, Berkeley reported nano-dispersed enzymes in Nature in 2021 at below 2 wt% in polycaprolactone and PLA, reaching up to 98 % polymer-to-small-molecule conversion in days in soil compost and in tap water, and stated the limit explicitly: polyolefins do not associate with enzymes. Neither result is recorded as carrying an EN 13432 certificate, and the Carbios film met home-composting conditions, a different standard from the industrial one this page covers.

The negative control is as informative as the positive result. Selke and colleagues at Michigan State University tested five biodegradation-promoting additives in polyethylene and PET in 2015 and found no significant increase in biodegradation in compost, in anaerobic digestion or in soil. An additive cannot give a polyolefin a chemistry it does not have, which is the dividing line between the enzymatic and the oxo routes. The hydrolase chemistry and the masterbatch route are set out on enzymatic biodegradation additives.

How Do You Make a Compostability or Biodegradability Claim Legally?#

A compostability or biodegradability claim is legal in both the EU and the United States only when it names the receiving environment, the timeframe and the standard the material was tested against, and both jurisdictions treat an unqualified claim as deceptive. The shared principle rules out the two shortest claims a marketing team wants to make. "Biodegradable" alone names no environment. "100 % biodegradable" adds a number to the wrong variable, since the percentage that matters is a percentage of organic carbon converted within a stated time in a stated environment, not a percentage of the product. What the two jurisdictions do not share is the enforcement mechanism: the EU reaches claims through a prohibition, a product duty and a policy framework, while the United States reaches them through deception law and state labelling statutes.

EU claim rules: the oxo ban, the PPWR and the Commission's claims framework#

EU law reaches compostability claims in three places: products made from oxo-degradable plastic have been prohibited since 3 July 2021 under Article 5 of Directive (EU) 2019/904, the PPWR requires four packaging types to be industrially compostable by 12 February 2028, and the Commission's policy framework requires every biodegradability claim to state the receiving environment and the timeframe. The three instruments operate at different levels, and a formulation has to clear all three:

• The oxo prohibition, which removes a material from the market entirely rather than restricting what may be said about it, and which targets the additive itself through the Article 3(3) definition
• The PPWR compostability duty under Article 9, which makes industrial compostability mandatory for permeable tea, coffee and other beverage bags, soft single-serve units and sticky fruit and vegetable labels, and which also requires consumers to be told that compostable packaging is not for home composting and not for littering
• The claims framework in COM(2022) 682, which requires a biodegradable claim to specify the receiving environment and the timeframe, and allows no biodegradability claim at all on litter-prone single-use plastic products

A 2024 directive on empowering consumers additionally restricts generic environmental claims across the EU, and its national transposition detail is outside what this page states. None of this amounts to a prohibition on the word "biodegradable": the EU restricts unqualified claims and prohibits a material, which are two different things, and the Packaging and Packaging Waste Regulation is the instrument that converts the compostability standard into a duty rather than a claim rule.

US claim rules: FTC Green Guides, California PRC 42357 and state labelling laws#

The FTC Green Guides at 16 CFR 260.8 treat an unqualified "degradable" claim as deceptive when the item does not completely decompose within one year after customary disposal, and they name oxo-degradable and oxo-biodegradable plastics explicitly. The one-year test is the operative number in US federal practice, and the guides add that disposal by landfill, by incinerator or by recycling cannot support an unqualified degradable claim at all, which removes the disposal routes most plastic packaging actually takes.

California goes further than the federal guides in both directions. California Public Resources Code 42357 prohibits labelling a plastic product "biodegradable", "degradable" or "decomposable", and prohibits implying that it breaks down, with green, beige or brown tinting on a bag counted as implying it. BPI's own US policy page records the same green, beige or brown tinting requirement from the certification side. For the two claims that remain available, the statute sets the evidence: "compostable" requires the ASTM specification, and "home compostable" requires OK compost HOME certification. Californian labelling requirements have been tightened further since.

Most US states define industrial compostability by reference to the ASTM standards rather than by their own criteria, so the federal deception rule and the Californian statute together cover most of the practical risk. The rest of the patchwork is mapped on US state laws on plastic additives.

How EN 13432 Works Together With the PPWR, EU 10/2011 and the POPs Rules#

An EN 13432 certificate proves compostability and nothing else: a compostable food-contact film still needs its Union list entries and its migration limits under Regulation (EU) No 10/2011, it still has to meet the PPWR's heavy-metal and PFAS limits, and a restricted additive is still restricted under REACH. The instruments are cumulative, not alternative, and reading them as alternatives is the single most expensive mistake available on this topic. Compostability is an end-of-life property. Food-contact authorisation is a migration property. A REACH restriction is a content property. Passing one says nothing about the other two.

One place the instruments pull in opposite directions deserves naming. Article 9(3) of the PPWR requires all packaging other than the four compostable categories, including packaging made from biodegradable polymers, to be designed for material recycling by 12 February 2028. A biodegradable polymer is therefore not an automatic route out of the recycling obligation, and choosing a compostable resin for a packaging format outside Article 9(1) adds a duty rather than removing one. All 6 additive-binding articles of the EU Packaging and Packaging Waste Regulation (PPWR) are set out on its own page.

Table T6: What each instrument adds to a compostable formulation

EN 13432 certifies an end-of-life route. It does not authorise a substance, replace a migration limit or lift a restriction. The substances removed from the market entirely are covered under POPs in plastics.

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What EN 13432 Does Not Tell You About Compostable Plastics and Their Additives#

EN 13432 measures what a material does in an industrial composting plant at 50 to 60 °C, which means it says nothing about a garden heap, nothing about soil or sea, and nothing about what a sorting line does with a compostable item that arrives in a recycling stream. Three questions follow from that boundary, and all three are asked constantly about compostable packaging: whether certified items actually compost outside a plant, why some collection systems refuse them, and whether "100 % biodegradable" means the same thing as compostable. This page answers those three from the evidence in its own source library and goes no further, because home-composting criteria, marine criteria and collection-system statistics are not in it. EN 13432 is one of 49 instruments and standards indexed under plastic additive regulations.

Do compostable plastics actually compost in the field, and do they leave microplastics?#

A certified compostable bag behaves completely differently outside an industrial plant: Napper and Thompson at the University of Plymouth found that a compostable bag disappeared in the sea within 3 months but was still present in soil after 27 months of a three-year exposure trial. Their 2019 study exposed biodegradable, oxo-biodegradable, compostable and HDPE bags in the sea, in soil and in open air, and no bag type showed reliable substantial deterioration across all three environments, while all bag types fragmented in open air within 9 months. PLA sets the same boundary from the polymer side, since full degradation needs temperatures above 60 °C and the material is reported to take close to three decades in home compost or soil, a figure our source library carries from a secondary reference. Zhang and colleagues published a 2018 study of nine EN 13432-compliant bioplastics in soil, named here without a result because its text has not been read.

The four criteria are written for one environment, so an additive cleared for industrial composting carries no claim about soil, sea or a garden heap, and nothing about what fragments or leaches there. What fragments and what leaches is on microplastics and additive leaching.

Is compostable plastic still plastic?#

Yes: a compostable material is a plastic, usually a bio-polyester such as PLA, PBAT or a PHA, and it is processed on the same extruders with the same additive families as any other polymer. PLA's glass transition of 60 to 65 °C and melting range of 130 to 180 °C are polymer properties like any others, and biodegradability follows from the chemical structure of the backbone rather than from the origin of its carbon. What changes with a compostable grade is the end-of-life route and therefore the additive package, not the fact of being a plastic.

Why some collection systems refuse compostable bags and recycling lines reject them#

A compostable item in a plastics recycling stream is a contaminant, which is why the PPWR requires all packaging other than the four compostable categories, including packaging made from biodegradable polymers, to be designed for material recycling by 12 February 2028. The same regulation requires consumers to be told that compostable packaging is not for home composting and not for littering. Our source library holds no collection-system acceptance rates and no national scheme detail, so this page states the design duty and its date and leaves municipal practice to the operators. The additive side of design for recycling explains why a compostable item behaves as a contaminant in a sorting line.

Is 100 % biodegradable the same as compostable?#

No: "100 % biodegradable" names no environment and no timeframe, while "compostable" means a material has passed 4 specific criteria in industrial composting, including at least 90 % biodegradation within 6 months. Biodegradability depends on chemical structure rather than on the origin of the carbon, and a claim becomes meaningful only once it carries its receiving environment and its timeframe, which is why the Commission's framework requires both. The polymer-by-polymer packages behind these grades are on additives for biodegradable and compostable plastics.