Four retailers that misleadingly advertised rayon clothing as bamboo face penalties totalling $2 million following action taken by the US Federal Trade Commission (FTC).

The proceedings sound a warning to retailers here that promote bamboo textiles as a “natural” choice for eco-conscious shoppers.

Bamboo is heralded for its ability to grow quickly with little or no need for pesticides. However, to turn bamboo into a soft wearable fabric, the cellulose in the plant has to be chemically dissolved and bleached. The end result of this process is rayon, also known as viscose, and no traits of the bamboo plant remain.

Bamboo can be mechanically processed, using a method similar to making flax into linen. But fabric produced this way isn’t the soft textile you find in clothes shops and is more expensive to manufacture. The FTC says there’s virtually no actual bamboo fibre on the market.

The commission recently published settlements reached with Bed Bath & Beyond (not related to Bed Bath & Beyond here), J.C. Penney, Nordstrom and Backcountry.com over their bamboo claims. Settlements with department store J.C. Penney and Backcountry.com also relate to claims their bamboo products had antimicrobial properties. The FTC says bamboo itself may have antimicrobial properties but there’s no evidence rayon made from bamboo retains these properties.

US labelling rules mean rayon textiles created using bamboo as the plant source can’t be labelled as bamboo and must be advertised as rayon.

Regulations here don’t specify how rayon derived from bamboo should be labelled. But it’s an offence under the Fair Trading Act for traders to mislead customers about the fibre content of textiles or the environmental attributes of products. Companies can be fined up to $600,000 for breaching the Act.