Comparing Compostable Bags

Not all professed “compostable” or “biodegradable” plastics are actually so. We put some to the test.
April/May 2011
http://www.motherearthnews.com/nature-and-environment/biodegradable-plastics-zmgz11zrog.aspx




In an effort to appeal to consumers who wish to reduce plastic bag pollution, new “bioplastic” bags have emerged on the market, claiming to be compostable. Testing commissioned by MOTHER EARTH NEWS, however, has found that many of the “100 percent compostable” claims manufacturers are making are misleading.

On our website last June, we published our findings, noting that bags from “Oxo-Biodegradable” plastic were particularly resistant to breakdown, even in commercial composting conditions.

An anonymous reader (under the name “Eco-Oxo”) criticized our research, claiming the Oxo bags break down if exposed to oxygen and heat, as opposed to typical composting conditions. So we asked our researchers at Woods End Laboratories to run another test exactly as Eco-Oxo suggested: They attached an “Oxo-Biodegradable” plastic bag to an outdoor fence, next to a regular plastic grocery store bag. After 12 weeks in the summer sun, the Oxo bag remained completely intact, while the regular bag had been shredded to pieces by sunlight and wind.

See photographs of the experiment and read more in Oxo-Biodegradable Bag Test.