Consumers often associate bamboo with sustainability. It is easy to grow, requires no pesticides or fertilizers, regenerates quickly when cut, and absorbs CO2 from the atmosphere. It can be a great choice for building materials, utensils, decor, and of course food. However, bamboo yarn is not as sustainable or eco-friendly, due to the factors I describe below.
Silky Bamboo Fiber = Rayon
All of the nice soft silky fiber that is labeled “bamboo” is actually rayon (or viscose, same thing). The U.S. Federal Trade Commission requires “bamboo” clothing and other textiles to be labeled as rayon, viscose, or “rayon from bamboo.” Retailers and manufacturers have been heavily fined for breaking these labeling rules. Yet somehow many yarn brands have been able to escape this rule, whether intentionally or not. Some yarn labels will list the fiber accurately as “rayon made from bamboo” or similar wording. But there are many brands that simply list “bamboo,” which is misleading.
How rayon is made
The process of converting bamboo pulp or any wood pulp into rayon is chemically intensive. Basically, it involves dissolving the bamboo cellulose in a chemical bath, letting it sit for a period, then running it through a spinneret that produces thin strands of fibers that land in yet another chemical bath producing the rayon. Chemicals such as carbon disulfide, sodium hydroxide, and sulfuric acid all aid in the process of transforming bamboo into a semi-synthetic fiber that is really no longer bamboo. It is rayon.
Health and environmental factors
Carbon disulfide exposure has been linked to several major health risks. Factories making rayon should be following a set of guidelines to ensure worker safety. But as consumers, we rarely know whether our rayon yarn has been produced with these safety measures in place. Also, once the rayon process is finished, factories often dump the chemical solutions into the environment causing pollution of waterways, air, and soil.
Manufacturers can use a closed loop process that captures and re-uses the chemical solutions, but only a portion factories use this process. There are international movements such as Dirty Fashion using group purchasing power to encourage Chinese manufacturers toward these closed loop methods, but we just aren’t there yet. (Patagonia and Eileen Fisher clothing brands have both either eliminated or cut down their use of bamboo viscose altogether and use Tencel Lyocell instead.)
Finally, China is the largest producer of bamboo products, so if you live in North America or Western Europe, your viscose traveled a long way, increasing its carbon footprint.
Is bamboo yarn “sustainable”?
The bamboo plant is very sustainable given its easy-to-grow nature. However, the chemically-intensive process required to produce bamboo yarn is less sustainable, especially when you factor the distance required to export the finished product.
Is rayon from bamboo better for the environment than new polyester, nylon, or acrylic? Yes. But “bamboo” textiles are not necessarily as sustainable or eco-friendly as the name implies.