The new revisions strengthen biodegradation requirements for compostable products.
Sep 11, 2026 — ASTM International’s plastics committee (D20) has approved two revisions to strengthen biodegradation requirements for the standard specification for labeling of plastics designed to be aerobically composted in municipal or industrial facilities (D6400), the foundational technical standard for compostable products. Together, the revisions strengthen D6400 by expanding the range of constituents that must independently demonstrate biodegradability and reducing the material eligible for testing allowances.
These revisions impact certification bodies, as well as manufacturers, brands, and retailers making claims of compliance with the standard. The revisions also give composters a stronger technical baseline for evaluating certified compostable products entering compost streams. The result is a more rigorous standard that better aligns with evolving international compostability benchmarks while remaining practical for manufacturers transitioning to the next generation of compostable materials.
ASTM's updated standard reflects a step forward for the industry, reducing the allowance for incidental constituents from 5% to 3% — a 40% reduction achieved through years of collaborative work between ASTM and the Biodegradable Products Institute (BPI). Like many manufactured products, compostable products can contain small amounts of inks, adhesives, coatings, colorants, processing aids, residuals, and other trace substances. The remaining allowance recognizes current practical functionality needs in packaging as fully biodegradable alternatives for certain components continue to develop, while maintaining the performance and appearance expected of products in the market.
Additionally, the revised standard expands independent biodegradation testing requirements for individual constituents from those present at 1–10% of dry mass to those present at 1–15%. Constituents above the threshold are addressed through the finished product’s overall compostability requirements and compliance review.
The revisions were developed over several years by the environmentally degradable plastics and biobased products subcommittee (D20.96) within D20.
"Reducing the allowance for incidental constituents by 40% represents a major milestone for the compostable products industry," said Margaret Eldridge, certification director at BPI. "Our members have spent the past five years working toward this goal by expanding the use of biodegradable inputs across formulations while continuing to deliver the performance and appearance consumers expect.”
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About BPI
The Biodegradable Products Institute (BPI) is North America's leading authority on compostable products and packaging, certifying over 50,000 products from collection bags to food containers. For more than two decades, BPI has given consumers confidence in compostability claims with the backing of science-based standards, while enabling authentically sustainable choices for brands and packagers. BPI champions a systems-wide transition to the circular bioeconomy through rigorous testing, policy advocacy, and industry collaboration, building the infrastructure for "A World Without Organic Waste"—where food scraps and certified compostable packaging become resources. BPI is a non-profit 501(c)(6). To learn more, visit www.bpiworld.org and follow us on LinkedIn.
