Companies that wish to gain and edge on their competitors and lure customers on the basis of their environmental friendliness may need to exercise some restraint. The Federal Trade Commission is proposing new guidelines it wants followed when using the phrases like “renewable energy,” “renewable materials,” and “carbon offset.”

“In recent years, businesses have increasingly used ‘green’ marketing to capture consumers’ attention and move Americans toward a more environmentally friendly future. But what companies think green claims mean and what consumers really understand are sometimes two different things,” said FTC Chairman Jon Leibowitz. “The proposed updates to the Green Guides will help businesses better align their product claims with consumer expectations.”

In addition to requiring judicious use of environmental language, the proposed rules would “…caution marketers not to use unqualified certifications or seals of approval – those that do not specify the basis for the certification.”

FTC said guideline on the use of terms such as “sustainable,” “natural,” and “organic” are already addressed by the U.S. Department of Agriculture’s National Organic Program and are not part of its proposal to avoid redundancy.

FTC is taking comments on the new guidelines.