Recently I read a thread on Ravelry that was very interesting, especially since I just bought a bamboo blend yarn. The Ravelry thread references a recent FTC Consumer Alert on the fiber content labeling practices of companies who sell clothing, linens, or other textile products. Here's the FTC Business Alert concerning bamboo labeling. These alerts were preceded by the FTC charging four companies with deceptive product labeling and advertising concerning bamboo. As of August 2009, all fabric labels now have to say something like "rayon from bamboo" or "bamboo rayon" rather than just "bamboo" since the majority of bamboo fabric is actually rayon. Also, proof (via testing) must be shown for products labeled as "bamboo" or those claiming to be derived from bamboo.
So what's all the hubbub about? Truth in labeling and possibly misleading "green" claims. Up until the FTC blew the whistle on the four companies, many products labeled as bamboo were in fact rayon derived from bamboo. Is rayon derived from bamboo still considered bamboo? No. Let me quote the FTC: Even when bamboo is the “plant source” used to create rayon, no traits of the original plant are left in the finished product. So, not only could companies sell rayon labeled misleadingly as bamboo. They could also get away with labeling products as bamboo rayon even if they were produced from cellulose resources other than bamboo. Their thinking? If there are no traces of bamboo left in the end product, why not use a cheaper cellulose source? With all the attractive qualities naturally inherent in bamboo, people might want to know if they're in fact buying bamboo or be certain that their bamboo rayon is actually derived from bamboo.
I'm no expert in the least. But from the little I've gleaned, bamboo can be processed mechanically or chemically. One process method that qualifies a fabric to be labeled as bamboo is mechanically crushing the woody parts and retting it with natural enzymes. Since this is the same process that's used for linen, sometimes the resulting fabric is called bamboo linen (or bamboo litrax). Chemical manufacturing processes and technologies other than the viscose process (to make rayon) are appearing which are more eco-friendly (e.g., the lyocell process, the process used to make TENCEL, can be used on bamboo cellulose) and are trying to retain bamboo's natural properties. See here and here for more information on how bamboo fabric is processed.
Truth in labeling and advertising. Are you getting what you think you're paying for? BTW, my bamboo blend yarn is labeled "rayon from bamboo." However, the website lists it simply as bamboo. The yarn is Spa by naturallycaron.com. Well, at least the yarn label is accurate. I found all this bamboo brouhaha interesting since it relates to yarn. I love my Regia Bamboo Jaywalker socks! I've also used SWTC Bamboo which is listed as 100% bamboo, and I have to say that I believe the label because it has a slightly scratchy, linen-like feel to it compared to some other bamboo yarns to which I've been exposed.