Curious about Compostables?
Composters across California have been testing compostable products in their systems - depending on the type of feedstock, hauling method, and compost system, different products get different results.
This page is meant to provide you with facts and data to help you make an informed decision about how to move forward with (or without) compostables. Scroll down for a list of case studies.
We've found through case studies that compostable products work best in a closed loop environment. This makes partnerships with institutions and commercial partners extremely valuable. Read on for a step by step overview of how to work with compostable products.
Different types of Compostable Foodware
Molded Fiber
Molded fiber products are widely accepted by composters across California. Molded fiber breaks down in a compost pile in a way that is similar to cardboard and paper products, which are compostable by default, as natural materials.
Paper/Wood Products
Paper and wood products are compostable by default. Composters often use wood chips as a carbon source in compost piles, and most composters accept food soiled paper.
Paper (Lined with PLA)
Paper products lined with PLA are more effective at holding liquid than unlined paper products. These products are often difficult to distinguish from paper products that are lined
Compostable Plastic
Molded fiber products are widely accepted by composters across California. Molded fiber breaks down in a compost pile in a way that is similar to cardboard and paper products, which are compostable by default, as natural materials.
Conventional Plastic (PET)
Compostable Plastic (PLA)
Understanding the Context of Compostable Plastic
Conventional plastics are ubiquitous in our world today. Very few plastics are recyclable, and conventional plastics often end up polluting our streets, cities, rivers, and oceans. Plastics recycling is a finite process, which degrades the plastic and requires additional inputs each time it is recycled, effectively extending the lifetime of a plastic product before it is finally disposed in either a landfill, or left as litter in our environment. Plastic recyclers have also expressed that they are drowning in the amount of plastics they are receiving. New and innovative plastic packaging presents unique challenges to recyclers, but even plastics #1, #2, and #5 are not getting recycled anywhere near their potential. As our world faces an increasing crisis in terms of conventional plastic pollution, industries are adapting to solve this existential issue.
Conventional plastics pose a huge challenge to composters. Plastic pollution often ends up in organic feedstocks, especially in municipal streams with high levels of contamination. Composters do everything in their power to reduce plastic contamination in their systems - including investing millions of dollars in technology and education. Nobody wants plastic in their compost - least of all, composters.
As California strives to increase the amount of food scraps rescued from landfill through SB1383, levels of contamination in green bins have increased in part due to the amount of conventional plastic used in food ware - disposable plates, cups, cutlery, and to-go containers.
Compostable foodware is meant to be the vehicle that keeps food waste out of the landfill. The most common compostable foodware includes bio-lined paper, molded fiber, and compostable plastic products. As an emergent technology, debates around what is "really" compostable are raging throughout the compost industry. Composting is a broad term for a range of composting methods, some of which are better suited to handle compostable food ware products. It’s important to note that compostable packaging is designed to break down aerobically. This means any facility using technology such as an anaerobic digester would not see great success with compostable packaging, specifically with bioplastics. As composters and compostable product manufacturers work together to determine the best materials to create clean compost, composters are facing another existential issue: telling the difference between compostable and conventional plastics.
Mitigating Contamination with CIRC
Contamination Reduction Check List
CIRC (Controls Intended to Remove Contamination) is guide developed by Eco-Products, in collaboration with composters, organics haulers, and large generators, to address the challenge of contamination from non-compostable materials in compost streams through a systems approach to Procurement, Operations, Communication, and Composter & Hauler Engagement.
CIRC is an open source, free to use tool to help institutions develop responsible organics management and resource recovery programs. This is a guide for what you need to know to develop a compostable foodware processing program.
Compostable Foodware Case Studies
San Diego Zoo + San Pasqual Valley Soils
The San Diego Zoo has a long history of sustainability goals and treating the environment better than you found it. As a popular amusement park for millions of visitors, there are a lot of foodservice products that are not able to be reused. This poses a challenge for a large venue trying to improve their sustainability. San Pasqual Valley Soils wants to be an even better neighbor, by potentially accepting a larger variety of compostable material along with the already established stream of manure and bedding.
This field test serves as the first step to better understand what breaks down efficiently in this specific system, and next testing the finished product to ensure it is safe to use back on the land. San Pasqual Valley Soils is a compost facility affiliated with and supporting Frank Konyn Dairy, the last remaining dairy farm in San Diego County. Additionally, we are the lucky neighbors of the San Diego Zoo Safari Park.
With the support of a CalPoly student researcher, we launched a composting pilot program to include certified compostable packaging with the San Diego Zoo’s animal manure and bedding.
The field test team utilized the Compostable Field-Testing Program (CFTP) as provided by the Compostable Research and Education Foundation (CREF) to help gather statistically significant data that could contribute to CREF's growing database of certified compostable degradation in different kinds of compost facilities. After 3 months of composting, the team led by the student researcher conducted a visual analysis and sent two compost samples to a lab San Pasqual uses for routine testing. The aim was to compare the composition as well as the resulting germination study to see how certified compostables can affect manure-based compost.
Future testing will be done to gather more data and better understand the role certified compostables could play if the Zoo were to send their compostables to San Pasqual. The next step is looking to align with the Zoo on any special events they have, help be there to sort, and send the used certified compostables to San Pasqual to conduct a bulk dose test.
Padres + Republic Services
The Padres, in collaboration with their partners and Republic Services, launched a composting program that includes certified compostable food service items and evaluates how well these items break down in a commercial setting. All compostable products used by vendors at Petco Park are tested at Republic’s Otay Sustainability Park Composting Facility in San Diego to ensure compatibility with the facility's systems.
The program aims to develop a closed-loop composting system that supports circularity, produces high-quality compost, and advances waste diversion—without compromising compost integrity. Initial results show that PLA-based foodware degrades more effectively than fiber-based options.
The resulting compost meets the US Composting Council’s Seal of Testing Assurance (STA) standards and is used successfully in Petco Park’s landscaping, effectively closing the loop on organics. This initiative provides a scalable model for other large venues and underscores the importance of collaboration and real-world testing in verifying compostable product performance.
What makes it compostable?
California is a geographically diverse landscape that grows much of our country’s produce. Compost is a valuable resource for growing healthy soils, healthy food, and a healthy environment. With this comes great responsibility to ensure anything in the organics stream, including certified compostables, meet high standards of disintegration, biodegradation, and ecotoxicity. To make sure compostables are safe for our compost, California aligns with ASTM’s standards for compostability.
Two major challenges
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Aligning the industry to utilize a standardized certification scheme to ensure that compostables break down in a compost piles.
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Mandating consistent, obvious, and recognizable on-product labelling for consumers and composters to be able to tell which items have been certified to meet ASTM standards and what items are contamination.
Relevant Research
Compostable Packaging Disintegration at Composting Facilities Study
Closed Loop Partners initiated a study with the US Composting Council, the Compost Research and Education Foundation, and the Biodegradable Products Institute. Read the study to learn about the conditions under which compostables can disintegrate in commercial facilities.
Certification Programs
Biodegradable Products Institute
BPI is the leading authority on compostable products and packaging in North America. All products certified by BPI meet ASTM standards for compostability, are subject to eligibility criteria around the connection to food scraps and yard trimmings, meet limits for total fluorine (PFAS), and must display the BPI Certification Mark. BPI’s certification program operates in conjunction with education and advocacy efforts designed to help keep food scraps and other organics out of landfills.
Certifications
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Commercial Compostability:
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The BPI Commercial Compostability Certification Scheme documents the standards, test methods, rules, and requirements used to evaluate items for BPI certification. It specifies how BPI applies the stated standards and methods to determine the testing required for certification of final products, resins and components, and is a useful reference to better understanding BPI certification. The scheme is maintained and updated by the BPI Standards and Procedures Committee
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Home Compostability (new!):
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BPI just announced their new Home Compostability Certification Scheme that enables more households to participate in circular living through a known and trusted certification. To earn the new certification, products must break down completely in the lower temperatures of backyard composting environments in addition to meeting existing certification criteria. This new certification will help improve accessibility to compost by allowing for individuals or community composters to include certified compostables while yielding them a high quality finished compost. This program will officially launch and begin accepting applications December 1st, 2025.
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Free Overs Testing
If you’re concerned an item isn’t certified compostable, or you see the item is BPI certified but didn’t breakdown at your facility, BPI offers free overs testing of compost where they will pay for the lab test and any associated costs like shipping to test if the product in question is certified. Click the button below to learn more.
Compost Manufacturing Alliance
CMA provides commercial composters an acceptance standard for compostables by performing field disintegration testing through several processing methods to ensure products adequately break down. CMA connects supply chain leaders with top compost manufacturing facilities nationwide to ensure mutual success as co-creators of compost and compostables.
Field Testing Program
CMA receives samples, logs them, and places them at composting site(s) for testing. At the end of the composting cycle, items are sifted from the feedstock and presented in a detailed photo report providing pass/fail information. CMA technical team offers support for meeting ASTM D6400 and D6868 requirements, while also working on a substrate innovation program for products in development.
Different strokes for different folks: There are multiple CMA certifications and approval schemes.
Certifications
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CMA-A = Certified for Aerated Static Pile Industrial Composting Systems
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CMA-I = Certified for Covered In-Vessel Industrial Composting Systems
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CMA-W = Certified for Windrow Industrial Composting Systems
Approval
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CMA-S = Approved as a composting substrate in industrial composting. Exclusively for a narrow set of qualifying items that provide carbon without excessive additives or treatments. This is not recognized as a certification.
California Policy Connection
SB54
In 2022, California passed Senate Bill 54, which requires that all single-use plastic packaging sold in California be recyclable or compostable by 2032. The bill also sets up a program to require the producers of plastic and compostable packaging to take on some of the responsibility for the end life of their products through an idea called Extended Producer Responsibility (EPR). Producers will pay into the program to help cover the costs of collecting, sorting, and processing their products after use, instead of consumers alone covering those costs. SB 54, along with other recent legislation, including SB 1383, which requires cities and counties across California to divert organic waste from landfills, are leading to significant increases in collection of compostable food serviceware, but also an increase in contamination of compost by traditional plastics.
Interested in learning more?
We bring together composters, compost users, and stakeholders, including non-profits, government agencies, educational institutions, and more.
Together, we grow healthy soil in California with compost.