Clarifying Biodegradable vs. Compostable in California


Products labeled “biodegradable” can also contaminate the recycling stream, but does that mean they should always be composted? Photo: Amanda Wills, Earth911

Biodegradable or compostable: These terms are often confusing for consumers trying to select an eco-friendly product.

Calif. State Senator Mark DeSaulnier, who represents a district east of San Francisco, aims to clear up the confusion for his state with Calif. Senate Bill 567, the Truthful Environmental Advertising in Plastics law. SB 567 would ban the use of the term “biodegradable” on plastic products and would only allow plastic products that meet certain standards to use the label “compostable.”

In 2008, DeSaulnier sponsored legislation that placed the same labeling restrictions on plastic bags and food packaging. SB 567 would extend the labeling requirements to all plastic products: pens, garbage cans, food storage containers and more.

Products carrying the term "biodegradable" are only compostable in a commercial composting system. Photo: Amanda Wills,

“Because companies know being environmental stewards is good marketing, we have the issue of greenwashing. That’s why we need truth in advertising,” DeSaulnier said.

Supporters of SB 567, including environmental advocacy group Californians Against Waste, say that calling a product “biodegradable” will make consumers more likely to litter the product, because they assume the product will be able to break down in a short amount of time and be harmless to the environment.

But there are limited national standards behind the term “biodegradable,” and a product that takes a hundred years to break down could use the label, according to Scott Smithline, director of legal and regulatory affairs at Californians Against Waste.

In its national standard-setting “Guides for the Use of Environmental Marketing Claims,” the Federal Trade Commission (FTC) defines a biodegradable product as one that breaks down in a “reasonable short period of time.”

The FTC is currently reviewing its “Green Guides” and is considering adding a specific time limit to the definition of biodegradability. But in the mean time, Smithline and others in Calif. want to place specific standards for biodegradable and compostable products.

READ: What You Need to Know About the FTC Green Guides

“’Biodegradable’ is meaningless outside of context,” Smithline said. “Any organic product is chemically biodegradable. Petroleum is biodegradable. Plastic bags are biodegradable in a hundred years.”

SB 567 backers also point out that modern landfills are actually designed to prevent the material inside from biodegrading, as the decomposition process releases methane emissions.

Products labeled “biodegradable” can also contaminate the recycling stream, causing problems for recycling processers, Smithline said.

Biodegradable products are often made from PETE plastic #1, the kind used in most disposable water bottles, with an additive that the manufacturer says makes the product degrade. At the recycling sorting facility, the optical scanner, used to identify plastics and non-plastics, will group the biodegradable plastic products with the plastics.

READ: Recycling Mystery – Bioplastics

Manufacturers that make new products out recycled plastic do not want biodegradable plastic in their material supply, Smithline said, in case the biodegradable additives cause the new durable products like carpet to break down over time.

Plastic products labeled “compostable,” made from poly lactic acid (PLA), are not identified as plastics by the recycling facility’s scanners. Compostable products don’t contaminate the recyclers’ material supply, even when consumers put the product into the wrong bin – the recycling bin – instead of the composting bin, if their city has a composting program, or the trash bin, absent a municipal composting program.

READ: Guide to Composting in the Summer

Unlike biodegradable products, compostable plastic products can be evaluated by a pass/fail test, developed by international standards organization ASTM International. SB 567 would require all plastic products claiming to be compostable – not just plastic bags and food packaging – to meet this standard.

The bill recently passed out of the Senate Appropriations Committee and now moves to the State Assembly. Last year, Governor Arnold Schwarzenegger vetoed a similar bill that DeSaulnier sponsored, even though Schwarzenegger signed the original bill that applied to plastic bags and food packaging. The senator hopes the new administration, Governor Jerry Brown, will sign the bill into law.

The trade association Plastics Environmental Council that opposes SB 567 could not be reached for comment.

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