While cities and states around the country crack down on the overuse of plastic shopping bags, the Federal Trade Commission is warning manufacturers of these bags to refrain from making eco-friendly claims about their products unless those claims can be proven in the real world.

According to the FTC, a number of companies are marketing their plastic bags as biodegradable or “oxodegradable” — meaning they will eventually degrade in the presence of oxygen — but these claims may be deceptive.

The FTC says that since most shopping bags are landfill-bound, and many landfills lack sufficient oxygen to cause degradation, the claims on these products are misleading.

“Contrary to the marketing, therefore, these bags may be no more biodegradable than ordinary plastic waste bags,” reads a statement from the FTC.

In 2012, the FTC revised its Guides For the Use of Environmental Marketing Claims (AKA, the “Green Guides”) to clarify that unqualified “degradable” or “biodegradable” claims for items generally destined for landfills, incinerators, and recycling facilities are deceptive because “these locations do not present conditions in which complete decomposition will occur within one year.”

The letters to 15 bag manufacturers explains that using terms like “oxodegradable” or “oxo biodegradable” is the same as using “biodegradable.” The companies were given a brief period of time to respond to the FTC and let the agency know if they have reliable scientific evidence to back up their claims, or if they plan to remove their oxodegradable claims from their marketing.

“If marketers don’t have reliable scientific evidence for their claims, they shouldn’t make them,” explains Jessica Rich, Director of the FTC’s Bureau of Consumer Protection. “Claims that products are environmentally friendly influence buyers, so it’s important they be accurate.”

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