The Federal Trade Commission made public that its staff sent letters to 15 businesses last month warning that their biodegradable claims related to “oxodegradable” plastic waste bags may be deceptive.

Oxodegradable plastic is supposedly made with an additive intended to cause it to degrade in the presence of oxygen. Most waste bags are intended to be deposited in landfills, however, where not enough oxygen likely exists for oxodegradable bags to completely degrade in the time consumers expect. Contrary to the marketing, these bags may be no more biodegradable than ordinary plastic waste bags when used as intended.

“If marketers don’t have reliable scientific evidence for their claims, they shouldn’t make them,” said 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.”

The FTC staff notified 15 marketers that they may be deceiving consumers based on the agency’s 2012 revisions to its Guides For the Use of Environmental Marketing Claims (the Green Guides). Based on studies about how consumers understand biodegradable claims, the Green Guides advise that unqualified “degradable” or “biodegradable” claims for items that are customarily disposed in landfills, incinerators, and recycling facilities are deceptive because these locations do not present conditions in which complete decomposition will occur within one year.

The FTC says it advised the businesses that buyers understand the terms “oxodegradable” or “oxo biodegradable” claims to mean the same thing as “biodegradable.” Staff identified the 15 businesses as part of its ongoing review of green claims in the marketplace.

The businesses are requested to respond to the warning letters and tell the staff if they will remove their oxodegradable claims from their marketing or if they have competent and reliable scientific evidence proving that their bags will biodegrade as advertised.

Despite that the information in this blog post was provided by the FTC, the staff is not disclosing the recipients of the letters.

The FTC expressly noted when providing this information that businesses who did not receive a letter should not assume that their claims are fine. The FTC has since the 2012 release of the updated Green Guides stepped up enforcement of environment claims from the use of renewable energy to VOCs in coatings, and more.