New containers that look like plastics but are labeled “compostable” or “polylactic acid (PLA)” are appearing in delis, grocery stores, and fast food restaurants. As well-meaning businesses work to green their practices, many are turning to these new, usually corn-based, products.

It may initially appear that disposable containers made from corn instead of traditional natural gas or oil should have environmental benefits. When considering the use of any new “green” material, consumers must ask whether the environmental benefits are real. We must also weigh potential gains against new problems the material may cause. It is important to ask if such a switch saves or uses more natural resources and energy and whether it reduces or increases carbon emissions to curb climate change.