compostable

Compostable describes materials that are capable of breaking down in a composting process to become stable, nutrient-rich compost. To be considered compostable, a material must biodegrade at an appropriate rate and leave behind residues that meet established criteria under defined conditions of temperature, moisture, and time. Compostable materials can be based on plant fibers, bioplastics, or treated paper, and are not the same as merely biodegradable, which does not specify an end product or a particular environment for decomposition.

Standards and certification help distinguish true compostables from other degradable materials. In the United States, compostable packaging is often labeled to standards such as ASTM D6400 or ASTM D6868. In Europe, EN 13432 sets criteria for industrial composting, and certifications such as OK compost INDUSTRIAL or OK compost HOME indicate suitability for specific composting settings. Because certifications focus on different environments, a product labeled compostable may not break down in a home compost pile or in a municipal recycling stream without appropriate facilities.

End-of-life considerations include using available composting options and avoiding contamination of recycling streams. Consumers should follow local guidelines, using municipal or home composting where permitted. Not all municipalities offer composting programs, and some compostables require industrial facilities to meet their standards. If mismanaged, compostable products can reduce compost quality or clog systems.

Examples include compostable bags, cutlery, cups with plant-based linings, food-service packaging, and certain paper products.