In what the Federal Trade Commission says is a wake-up call, the agency has told dozens of retailers to stop labeling and promoting rayon textiles as bamboo. The FTC warned the retailers that they might be breaking the law.

"We need to make sure companies use proper labeling and advertising in their efforts to appeal to environmentally conscious consumers," said David C. Vladeck, director of the agency's Bureau of Consumer Protection, in a press release. Among the companies warned by the FTC are Amazon.com, Bed Bath & Beyond, Costco, Kmart, Lands' End, Sears, Target, and Walmart.

The February 3rd action by the FTC follows its move last August to charge four clothing and textile manufacturers with making false product claims about bamboo-based products. Read "Buzzword: Bamboo-zle" for more details.

Rayon is a manufactured fiber made from the cellulose that comes from trees and plants, and treated with toxic chemicals that emit dangerous air pollution, according to the FTC. The cellulose could come from bamboo or any other plant or tree.

As the number of fabric products marketed as bamboo has increased in recent years so too have misleading claims, including products claiming to retain bamboo's antimicrobial properties. Learn more about this issue in the FTC's "Have You Been Bamboozled By Bamboo Fabrics?"

—Kimberly Janeway

Essential reading: Look for our full report on sheets, including ones labeled as being made from bamboo, in the May issue of Consumer Reports, available on ConsumerReports.org and newsstand in early April.