A certificate says a product can compost. The Compost Manufacturing Alliance (CMA) answers the next question, which is whether it will, in the facility that actually collects your bins. The alliance is made up of composters, and it tests products twice: a laboratory review, then a field test in working facilities under the conditions those facilities really run.
The four labels
Composting methods differ, and a product that breaks down in one may not in another, so CMA issues separate approvals.
- CMA-I, for in-vessel composting.
- CMA-W, for windrow composting, the long outdoor rows.
- CMA-A, for aerated static piles.
- CMA-S, for use as a substrate.
A product carries the labels for the methods it passed. If your local facility runs windrows, CMA-W is the one that matters.
How to use it
The accepted-products list on CMA's site held 321 products when checked in October 2026 and can be filtered by product type and label. Find out which method your hauler's facility uses, then filter for it. Combined with BPI's catalogue, this is as close as a restaurant can get to knowing that a compostable container will be composted rather than landfilled.
A note on currency
The site's footer carried a 2024–2025 copyright when checked, so confirm the list is still being maintained before relying on it for a large purchase.