While some dog owners stick to tried-and-true methods of picking up their canine pals’ waste with the aid of plastic shopping bags, that’s a lot of plastic going into landfills. This is why there are several companies selling poo-collection bags labeled “biodegradable” or “compostable.” But the Federal Trade Commission is warning a number of the companies that make and market these products that they may be running afoul of laws against deceptive advertising.

According to the FTC, it has sent letters to 20 different manufacturers and marketers of supposedly environmentally friendly dog waste bags, warning them that their claims of biodegradability or compostability may be considered deceptive, and advising these companies on how to revise their marketing so that it no longer crosses that line.

The FTC’s guidelines for Environmental Marketing Claims [PDF] say that if a company is going to make an unqualified claim of a product being “biodegradable,” it should completely break down into its natural components within one year after being thrown out. But because these bags go to landfills, the FTC says the material is unlikely to completely break down in a year, if it degrades at all.

Those same guidelines state that unqualified “compostable” claims should be used for products that will safely break down at the same rate as natural products, like leaves and grass clippings, in home compost piles. However, the FTC says that composting dog waste is not safe in most home compost setups and that very few larger compost facilities accept dog waste.

“Consumers looking to buy environmentally friendly products should not have to guess whether the claims made are accurate,” said Jessica Rich, Director of the FTC’s Bureau of Consumer Protection.

The FTC is not yet releasing the names of companies that received warning letters.

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