Many San Diego households now separate food scraps for composting, and products labeled “compostable” are marketed as an easy way to do it. Reports in 2024 raised questions about whether some of those products live up to their labels, and whether they belong in San Diego’s green bins at all.
The Issue with “Compostable” Bags
California is requiring cities and counties to collect food waste for recycling, and the City of San Diego now accepts food scraps in residential green bins. For the system to work, scraps must go into the bin loose or wrapped in materials the composting facility can process.
A 2024 investigation in San Diego focused on bags marketed by Crown Poly under the “Hippo Sak” brand name. The bags, sold at Trader Joe’s and other stores, were labeled as “compostable” in home and commercial composting systems.
Several issues were reported:
- Certification claims: The company cited certifications from U.S. and European organizations, but those certifications proved difficult to verify. BPI, a leading certifier of compostable packaging in North America, could not share research or test results. TÜV AUSTRIA, a European certifier, reported that Crown Poly held no valid certificates from it and said it had been trying, without success, to get the company to remove the claims from its products and website.
- Not accepted by the city: The City of San Diego does not accept these bags in its composting program. The city’s Environmental Services Department has said such products cause contamination and diminish the quality of the finished compost.
- Breakdown time: The manufacturer stated that its bags degrade in less than 180 days, much longer than food scraps themselves take to break down, which raises questions about how well they work in real composting conditions.
Why It Matters to Consumers
Shoppers who pay more for a “compostable” product are usually trying to make an environmentally responsible choice. When a product’s label does not match how it is actually handled by local composting programs, consumers may pay extra for a benefit they do not receive, and the bags can end up contaminating the compost the city produces.
What San Diego Residents Should Know
The City of San Diego says plastic bags are not accepted in the green bin, including plant-based bags labeled “compostable.” Paper bags are accepted. The city suggests these steps instead:
- Drain liquid from very wet food scraps first.
- Wrap scraps in newspaper, a paper bag, or used paper napkins or paper towels.
- Collect scraps in a kitchen pail and empty it into the green bin.
- To reduce odors, keep scraps in the freezer or refrigerator until collection day.
Residents outside the City of San Diego should check their own city’s or hauler’s rules, because accepted materials vary across San Diego County.
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