Compost Manufacturing Alliance – Windrow (CMA-W) Change


header image
Skip Navigation LinksHome » Departments » Trash, Recycling & Compost » Compost Manufacturing Alliance – Windrow (CMA-W) Change

​​​​​​​​​​​​​Webinar recording coming soon

​Thank you if you were able to join us at one of our webinars about the CMA-W switch. We will be posting the recording soon. In the meantime, you can read the information below about the upcoming change. If you are interested, sign up for commercial compost by completing this online form​. For information on costs of service, see this business trash page​. ​​

The CMA-W W​ebinar slides​ (PDF) are available now.


As of January 1, 2024, the City of Ann Arbor and it's compost facility operator, WeCare Denali (WeCare), will no longer accept BPI-only certified material in compost carts or at the city's compost facility. Instead, only selected products identified as being certified "CMA-W", short for Compost Manufacturing Alliance - Windrow, and made of fiber material will be accepted.  A list is ​available (PDF) of currently selected and certified CMA-W, fiber only products that will be accepted by our composting partner, WeCare. Also, bamboo and palm leaf products are currently excluded as they do not break down within the process timeframes. 

The change stems from the following reasons:

  • Compostable plastics can be nearly indistinguishable from traditional petroleum-based plastics

  • Which leads to traditional plastics in the compost stream and compostable materials in the recycling stream.  

  • CMA certification adds a field test for compostability, in addition to lab testing, which ensures the items break down appropriately in a real-world compost application.

Compost manufacturers formed the Compost Manufacturing Alliance (CMA) in 2017 to begin researching and field testing manufactured compostable products. CMA now offers a variety of certifications to products that have ​met industry standards for properly breaking down in a myriad of ways, including compost windrows like those used at the Ann Arbor compost site. 

This change may be frustrating, especially for businesses, organizations or individuals who have stocks of this material. However, the benefits to improving our environment and in meeting the city's climate change goals are well worth the effort. 

To help the community understand this shift, the city will:

  • hold outreach and trainings to those most heavily invested in manufactured compostable products such as food businesses

  • conduct community and outreach communications via print and digital channels

To see what is allowed in Ann Arbor compost through 2023, please visit our compost page. 

Distributors of CMA-W products​

BGreen - 734.214.3000

My Green Michigan - 877.304.5810
[email protected]

Highland Supply - 248.714.8355​

Green Safe Products - 313.326.3100​

You can also download our CMA-W Distributers Flyer​ (PDF)​.