ASTM D6400-23: Compostable Plastics Labeling

At an industrial composting facility, towering piles of organic material generate heat as billions of microorganisms go to work. Food scraps, yard waste, and compostable products slowly break down, becoming something entirely new. Not every plastic item, however, can withstand this test. ASTM D6400-23: Standard Specification for Labeling of Plastics Designed to be Aerobically Composted in Municipal or Industrial Facilities defines the requirements plastics must meet to be considered compostable in industrial composting environments.

What Are Compostable Plastics?

Compostable plastics are specifically engineered to break down through biological treatment at industrial composting facilities, relying on precise levels of heat (usually 55°C to 70°C), moisture, and aeration to decompose into carbon dioxide, water, and biomass

Why Most Composting Facilities Reject Plastic

Because plastics require prolonged processing times and risk contaminating organic compost, most municipal composting facilities reject them. Composters cannot risk ruining their product, so they often reject any plastic-like material to protect their bottom line. ASTM D6400-23 provides a solution by defining rigorous criteria for compostability, helping distinguish materials that can be successfully processed in commercial composting facilities from those that cannot.

What Is ASTM D6400-23?

ASTM D6400-23 covers plastics and products made from plastics that are designed to be composted under aerobic conditions in municipal and industrial aerobic composting facilities, where thermophilic conditions are achieved.

This standard is intended to establish the requirements for labeling of materials and products, including packaging made from plastics, as “compostable in aerobic municipal and industrial composting facilities.

Supporting a Circular Economy

As organizations seek more sustainable packaging and product solutions, ASTM D6400-23 plays a vital role in supporting the development and verification of compostable plastic materials. By providing clear, science-based requirements, the standard helps assure that compostable plastics perform as intended while contributing to broader waste reduction and circular economy goals.

Do Compostable Plastics Biodegrade on Their Own?

One of the most common misconceptions about compostable plastics is that they will naturally break down wherever they are discarded. In reality, compostable plastics are designed to decompose under the controlled conditions found in commercial and municipal composting facilities—not in the open environment, landfills, or marine ecosystems. These facilities maintain the elevated temperatures, moisture levels, oxygen availability, and processing times necessary for effective biodegradation.

Depending on the material and composting conditions, complete disintegration may take up to 180 days. Because of these specialized requirements, access to appropriate composting infrastructure remains critical. More than 85 composting facilities across the United States openly accept certified compostable plastics, while others evaluate such materials on a case-by-case basis.

ASTM D6400-23 assures that products labeled as compostable are capable of breaking down as intended within these industrial composting systems, supporting both waste diversion efforts and the production of high-quality compost.