bamboo clothing
Zeyus Media via Flickr

Versatile bamboo has more uses than product in the world. Growing bamboo is probably more sustainable than any other crop. The sustainability of bamboo fabric has been a matter of controversy from the start. This article will look at the environmental impact of bamboo fabric and compare it with alternatives. Everything has its pros and cons. Don’t bother waiting for anything with no negative environmental impact. We’re  not allowed to go naked, after all. Weather often wouldn’t permit even if we were. 

Bamboo is a wonderfully sustainable crop for many reasons. For one thing, it’s a grass that grows from an underground rhizome. Harvesting it doesn’t kill it. A new culm grows back quickly. 

Therefore, it is not necessary to till the soil every year to plant another crop. Bamboo presents no soil erosion issues. Bamboo offers more biomass per acre than cotton. Therefore, it takes in more carbon dioxide and produces more oxygen. 

What’s more, bamboo doesn’t need fertilizer, pesticides, or irrigation.  It doesn’t deplete the soil. Tending it is less labor intensive than most crops and doesn’t need heavy machinery.

About the only environmental downside to bamboo as a crop is the growing tendency to plant it in monocultures. 

Two kinds of bamboo fabric

Photo by Peggy Reeves Sanday
via Wikimedia Commons

Some bamboo fabric is made by a strictly mechanical process much like making linen from flax.

Linen, of course, is one of the oldest fabrics known to man. First, it requires growing and harvesting a crop. Retting it in water leaves a gooey mass that someone has to comb, spin into yarn, and weave on a loom. It is labor intensive and time consuming to make. 

It’s easy enough to find traditional linen fabric from flax, but little bamboo becomes bamboo linen. Most bamboo for fabric becomes bamboo rayon. 

The process for making rayon originated in the 1880s using wood fiber. It’s not quite a natural fabric because of the chemical processes needed to make it. But since it starts with a natural  plant, it’s not quite a synthetic fabric, either. Nylon, polyester, etc. are plastic made from petroleum.

Making rayon requires dissolving plant fibers in harsh chemicals, It’s much faster than the retting process for linen. This chemical bath, too, results in a pulpy mass. Nothing remains of the original fiber. Instead of combing and spinning, the goo is extruded through a spinneret. The resulting fiber is not yet thread. Another solvent must first harden it. The chemicals used include lye, chlorine bleach, sulfuric acid, and carbon disulfide.

For decades, factories would simply discharge used chemicals into a waterway. In recent decades, the public and government regulators have forced companies to clean up their act. Some, at least, of these chemicals are recovered and reused. Not nearly enough.

The process of making rayon from bamboo became commercially available only in 2006. Manufacturers immediately began to claim that they had introduced a new,  eco-friendly fabric. 

The Federal Trade Commission quickly cried foul. I have lately seen articles that approve of its clamping down on “greenwashing.” But not so fast. 

The FTC case against bamboo fabric

The FTC first issued its findings in 2009. I first investigated bamboo fabric in 2012. At the time, the FTC website had an article titled “Have You Been Bamboozled by Bamboo Fabrics.” The same URL now goes to a different page with much shorter text and headline but the same disapproval of bamboo fabric. Here is the part of the earlier text from my notes:

Looking to be a more environmentally conscious shopper? You’ve probably heard about bamboo. Bamboo stands out for its ability to grow quickly with little or no need for pesticides, and it is used in a variety of products, from flooring to furniture. But when it comes to soft bamboo textiles, like shirts or sheets, there’s a catch: they’re actually rayon.

The Federal Trade Commission, the nation’s consumer protection agency, wants you to know that the soft “bamboo” fabrics on the market today are rayon. They are made using toxic chemicals in a process that releases pollutants into the air. Extracting bamboo fibers is expensive and time-consuming, and textiles made just from bamboo fiber don’t feel silky smooth.

There’s also no evidence that rayon made from bamboo retains the antimicrobial properties of the bamboo plant, as some sellers and manufacturers claim. Even when bamboo is the “plant source” used to create rayon, no traits of the original plant are left in the finished product.

Companies that claim a product is “bamboo” should have reliable evidence, like scientific tests and analyses, to show that it’s made of actual bamboo fiber.

The trouble with the FTC’s case

The claim of deceptive labeling.

bed. bamboo fabric

If any manufacturer ever claimed its bamboo rayon products were made of natural fiber, it would indeed be deceptive. But in my research, I looked at a lot of product descriptions from a lot of retailers and manufacturers. Every one of them disclosed it was made of  bamboo rayon.

Why did the FTC demand scientific tests? Rayon is not made of natural fiber, but bamboo rayon is made of bamboo. What else are companies supposed to call it if not bamboo? The FTC alleged deception where there was none.

Antimicrobial properties

As for antimicrobial properties, it appears that no research had been conducted at the time of the FTC’s legal actions. Manufacturers had no scientific evidence to back claims that bamboo fabric is antimicrobial. The FTC had none to the contrary. 

A study in 2011 compared antimicrobial properties of regenerated bamboo (that is, bamboo rayon) with both cotton and viscose rayon from wood. Cotton, used as the control, has no antimicrobial properties. Neither does wood fiber used to make rayon. Natural bamboo fabric, on the other hand, is antimicrobial.

Experiments found antimicrobial properties in  both kinds of rayon. Neither killed 100% of the bacteria. The tests involved two different kinds of bacteria. Results for two kinds of rayon were comparable for one. The bamboo rayon killed significantly more of the other than the wood bacteria.

The only way for the wood rayon to kill bacteria is with sulfur residue from the manufacturing process. Testing found more sulfur on the wood bacteria than the rayon bacteria. Did any of the bamboo’s properties remain in the bamboo rayon? The conclusion did not endorse the positions of either the manufacturers or the FTC.

These findings led to the conclusion that the claims made regarding the bacteriostatic or antimicrobial properties of regenerated bamboo cannot be proved false. 

Biodegradability

In a passage I didn’t copy and paste, the FTC further claimed that bamboo rayon is not biodegradable. 

A study published in 2004 compared the biodegradability of rayon, cotton, linen, and acetate. The rayon actually showed the highest biodegradability—higher than either of the natural fabrics. FTC scientists should have known about that kind of research.

Since bamboo rayon was not yet available, that study must have used rayon made from wood fiber. There seems no reason why rayon made from anything else would give any different results. 

But contradicting a scholarly research study isn’t the worst problem with the FTC’s stance.

The ordinary definition of “biodegradable” is “capable of being decomposed by natural biological processes” (American Heritage Dictionary). 

The FTC didn’t use that definition. It required that materials break down in a short amount of time after “customary disposal.” By that definition, therefore, not even garbage is biodegradable after customary disposal! Nothing breaks down in a short amount of time in a modern landfill. 

Sustainability, bamboo rayon, and alternatives

bamboo fabric

Rayon, including bamboo rayon,  comes in three different varieties: viscose, modal, and lyocell. Most of it is viscose. Lyocell comes from a slightly more eco-friendly process.

No one can deny that bamboo is among the most eco-friendly crops. The chemicals necessary to transform it into rayon clearly pose environmental problems. What are the alternatives?

Polyester, nylon, and other synthetics

Synthetic fabrics are petrochemicals. They include all the environmental costs of extracting oil from the ground. I’ll not try to compare the chemicals used to turn oil into fabric with the ones for turning bamboo into rayon, but they can’t be much of an improvement, can they? 

Perhaps the biggest environmental drawback of synthetics is microplastics. All fabrics shed microparticles in the laundry. Everything but synthetics is biodegradable, or at least more biodegradable than plastic. Just think of how much microplastic poured into the oceans from our washing machines before anyone realized it was a problem! 

I’m sure scientists are looking for ways to mitigate microplastic pollution, but nothing is likely to become available anytime soon. 

At worst, bamboo rayon is more sustainable than synthetics.

Rayon

Rayon from bamboo is also more sustainable than rayon from trees. Making rayon requires all the same chemical processes regardless of the fiber source.

Harvesting trees kills them. (There are harvesting methods that don’t kill trees, but they’re not used at commercial scale.) It takes a while for new trees planted in their place to grow enough to hold onto the soil. Soil erosion can result from harvesting wood, but not bamboo.

Cotton

thread. bamboo fabric

Cotton requires more water than most crops. And it must be planted every year. Conventional cotton growing also extensively uses synthetic fertilizer and pesticides. Beyond the chemicals used to grow cotton, growers often spray exfoliants on it at harvest time to make the leaves fall on the ground. 

Making the cotton into fabric requires the following:

  • a chemical stiffener before weaving 
  • bleach
  • lye to strengthen the fabric and improve dyeing
  • finishers to relax fibers and prevent wrinkling and help the fabric hold color
  • formaldehyde for fiber stability

 Growing organic cotton uses “natural” pesticides such as Bacillus thuringiensis, which while not a synthetic chemical is still toxic. The manufacturing process doesn’t include any of the chemicals listed above. It is certainly less toxic.

Organic cotton is necessarily more expensive than ordinary cotton. Foregoing chemical pesticides results in more of the crop lost to insects and weeds. Organic cotton therefore requires more land to yield the same amount of product as conventional cotton. Large harvesting machines in conventional cotton growing work best after application of exfoliants, which organic farmers can’t use. So organic cotton must often be hand-picked.   

Choose between a more sustainable crop and a more sustainable manufacturing process.

Silk

Silkworms live on mulberry trees grown on marginal land not much good for anything else. No pesticides are used on those trees. They would harm the silkworms. On the other hand, the trees appear to require a lot of water, but not as much as much as cotton. 

Raising silkworms requires a lot of energy to control temperature and humidity. All in all, silk might be more sustainable than the other alternatives to bamboo rayon. But some environmentalists paint it as a villain.

I’ll not try to describe wool. I don’t suppose anyone would turn to it as an alternative to rayon. 

When you consider the chemicals required to make bamboo rayon, it doesn’t look very eco-friendly. When you compare bamboo rayon to any other alternative, it doesn’t look so bad. 

We must use fabric of some kind. Picky environmentalists have labeled every one of them an ecological disaster. You’ll just have to pick the least bad according to what issues matter the most to you. 

Sources:
Bamboo: the holy grail of fabric? or Pandora’s box? / Rachel, Contrado. November  29, 2019 
Chemicals in fabric / Joanne Denekamp, All About Quilts. [2019]
A comparative study of regenerated bamboo, cotton and viscose rayon fabrics. Part 2: antimicrobial properties / A. Gericke and J. Van der Pol, Journal of Consumer Sciences 39 (2011)
Organic cotton processing / Edward Menezes, Fibre2Fashion
Why does silk have such a bad environmental rap? / Aiden Wicker, Ecocult. March 4, 2020

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