WASHINGTON — The Federal Trade Commission is proposing revisions to its “green guides” it gives to marketers to help them avoid making misleading environmental claims.

“In recent years, businesses have increasingly used ‘green’ marketing to capture consumers’ attention and move Americans toward a more environmentally friendly future,” said Jon Leibowitz, chairman of the F.T.C. “But what companies think green claims mean and what consumers really understand are sometimes two different things. The proposed updates to the Green Guides will help businesses better align their product claims with consumer expectations.”

The revisions warn marketers to not make blanket, general claims that a product is ‘environmentally friendly’ or ‘eco-friendly’ because consumers are likely to take such claims to mean that the product has specific and far-reaching environmental benefits. The revisions also tell marketers not to use unqualified certifications or seals of approval and advise marketers how consumers are likely to understand certain environmental claims. Specifically, if a marketer claims the product is ‘degradable’ it should decompose in no more than one year.

The revisions also provide advice about the use of renewable materials and renewable energy, a topic not currently in the Guides. It also provides new advice about carbon offset claims and recommends marketers disclose if emission reductions that are being offset by the consumer’s purchase will not occur within two years.

The F.T.C. is seeking comment on all aspects of the proposal until Dec. 10.

The Green Guides were first issued in 1992 and provide general principles that apply to all environmental marketing claims, how consumers are likely to interpret specific claims and how marketers can quality their claims to avoid deceiving consumers. The Guides were updated in 1996 and 1998.