“Have You Been Bamboozled by Bamboo Fabrics?”  This is the title of a recent consumer alert by the US’s Federal Trade Commission.

The charge is basically one of greenwashing – of exaggerated or untruthful eco-friendly claims in marketing.

The FTC alerts points out the following:

1) “Soft ‘bamboo’ fabrics on the market are rayon.”  In other words, bamboo doesn’t easily break down into handy fibers that can then be easily woven into nice soft textiles.  Rather, they are man-made fibers produced with ”toxic chemicals in a process that releases pollutants into the air.”  (More on bamboo textiles here.)

2) Claims are being made that rayon made from bamboo has antimicrobial properties.  The FTC says there is no evidence for this.

3) Companies that claims a fiber is made from bamboo should have it verified through scientific testing, since it’s otherwise not possible to tell the original plant source.

Source:  http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt160.shtm

There are two processes for converting the bamboo plant into a fiber: viscose and retting. The main environmental issue specific to bamboo fabric has to do with how the most common type of fabric is manufactured.

Retted Bamboo

Retting mechanically crushes the plant and then uses nature’s natural tendency to break down materials (aided by bacteria or enzymes) to loosen the fibers from the woody tissue.  Typically used for jute and linen, it is a time consuming and expensive process (compared with modern chemical processing of bamboo) and the resulting product isn’t as soft or shiny.  Sometimes called bamboo linen, this fiber is produced without significant chemical inputs, and so is much more environmentally friendly.  While fairly rare, it is emerging on the market and there are rumors of increasing manufacturers of this production type. 

Viscose Bamboo

Most bamboo fibers on the market are actually rayon, or regenerated cellulose (plant material), and most of those are made using a viscose production process. 

For this method, the plant material is treated with sodium hydroxide (i.e., caustic soda or lye) and then carbon disulfide to get a slurry, called, surprisingly, viscose.  The viscose is then forced through a spinneret to get long strands of fibers, which are hardened in a chemical bath, then washed and bleached. 

This bit of the process isn’t much different from the production of other rayons, and the main chemical used, sodium hydroxide, is approved for by the Global Organic Textile Standard (GOTS), for use with organic cotton.  However, as with other rayons, the quantity of sodium hydroxide used, along with the other highly toxic chemicals, pose serious threats to human health and the environment (in production that is – not in the final product).

While not as sustainable as using no chemicals at all, manufacturing viscose wouldn’t be too bad if the process was ”closed loop”, whereby the chemicals are captured and reclaimed. 

A number of websites suggest that bamboo viscose fiber is made by one company in China, the Jigao Chemical Fiber Company, who owns the patent.  While a Scientific America article suggests that Jigao has a “sophisticated wastewater treatment system”, it is not clear exactly what these means and where the chemicals are disposed, and it is certainly not closed loop.

Other Textile Processes

All fibers are spun into yarns, which are then woven or knitted into fabrics.  Usually, at some point those fibers, yarns, or fabrics are dyed.  Conventional dyes typically contain heavy metals such as lead and mercury, as well as chemicals that cause DNA mutations or are endocrine disruptors.

Again, the issue is the impact on the health of the workers and to the environment.  How are these materials handled during production? Are they treated before leaving the factory.  In many cases they aren’t, and the pollutants find their way into the water system.

Finally, finishes (sometime mechanical, sometimes chemical) are applied to the piece of fabric before it reaches it’s final form.  Again, how are these chemicals handled?

Greenwashing vs Green Bamboo Textile

So is conventional bamboo (rayon) fabric eco-friendly?  Does the fact that the raw material comes from a more environmentally sustainable crop make it a eco textile?  I don’t think so, although it does seem to have an eco advantage over other rayons.

It would be interesting to see a life cycle assessment comparing bamboo rayon to conventional and organic cotton.  Organic cotton can be dyed and finished with the same toxic chemicals as bamboo.  I’m not sure how the bamboo version would stack up.  And, of course, there are a lot of variables (unbleached? natural dyes? no toxic finishes? water conservation measures for the cotton?).

The textile industry is notorious for it’s negative environmental impact.  While the growing and harvesting of bamboo is generally eco friendly, the viscose process negates much of that benefit.  But some companies are really trying to change things, and I expect there will be more options in the future.

So what do you do?

Want soft, luscious bamboo towels or sheets?  Just ignore the hype and enjoy the product, knowing that what you are getting isn’t as environmentally friendly as it claims.

Want truly sustainable bamboo textiles?  Seek unbleached, retted bamboo colored with environmentally sensitive dyes.  There’s a tiny little bit out there, and demanding more will only help grow the market.  Or wait for a ”closed loop” bamboo rayon – maybe even made by an ISO 14001 certified manufacturer – but don’t hold your breath.

Sources:

• Bamboo Boom: Is this material for you?  Scientific America
• Bamboo & the FTC, O Ecotextiles blog
• Bamboo: Facts behind the fiber, Organic Clothing Blog

Eco advantages of bamboo

• It is a rapidly renewable material.  As an incredibly fast growing grass, bamboo replenishes itself and is harvestable in as little as 3 years (some manufacturer wait at least 5 years for quality), and is thus rapidly renewable.  This is because to harvest, bamboo is cut, leaving the root structure intact for the plant to regenerate.  Contrast this to the wood that has historically been used – which take 25 to 50 years to reach maturity (or even 120 years for some hardwoods) and can’t regrow after being harvested.
• This same root structure holds soil together, making bamboo a great plant for areas with soil erosion problems.
• It has a high level of biomass, stores considerably more (4 times according to some websites) CO2 than similar trees, and according to Lucy Siegle, bamboo “releases 35 per cent more oxygen than the equivalent amount of trees.”
• Darker colours are achieved through carbonization, thereby minimizing harmful dyes.
• It is possible to get FSC certified bamboo.

Eco disadvantages of bamboo

• Urea formaldehyde (UF) resins are typically used which emit volatile organic compounds (VOCs) that are harmful to indoor air quality.  However, ”bamboo flooring uses a relatively small amount compared with other materials, such as particleboards” (BuildingGreen.com). Floating floors will off-gas higher amounts of VOCs due to greater use of adhesives.
• Mostly Chinese-made, “manufacturers use potentially toxic binders, finishes, and other chemicals; create lots of solid waste; and run equipment that may be dangerous and polluting” (BuildingGreen.com).
• Some colours (including metallic finishes) are the result of toxic dyes.
• Bamboo has high transportation miles, being harvested and manufactured in Asia, and then transported to Europe and America.  However, transportation by ocean freight is considerably more efficient than by land.  Thus BuildingGreen.com claims that (at least for North America), “the transportation energy of a Chinese bamboo flooring product may be comparable to a domestic hardwood flooring product.”

Eco ambiguities of bamboo

There is conflicting information from these two respected sources in regards to land use and pesticides/fertilizers:

• BuildingGreen.com states: “The bamboo species most often used to make flooring…matures in three years; is self-regenerating; and uses little or no fertilizers and pesticides. Chemical use is more common on plantations where edible shoots are grown.”
• Treehugger states: “it is clear that bamboo is not necessarily being managed in a sustainable fashion….forests are being cleared to grow it and it is becoming a monoculture. Although it is claimed that fertilizers are not necessary, in fact they are being used to increase yield.”

The risk to pandas has also been cited:

• Most sources I’ve read are aligned with this BuildingGreen.com statement: “Most bamboo flooring available in the North American market is made in Hunan Province in southern China with bamboo harvested from natural and plantation groves there. (Pandas, which live at much higher elevations, don’t eat this kind of bamboo.)”
• However, Lucy Siegle states: “Out of 1,600 bamboo species, commercial growers focus on just 38 of the fastest growing, leading to the spectre of more monocultures. The World Conservation Union’s Red List of endangered species includes 27 species of woody bamboo, including that preferred by giant pandas and west African mountain gorillas.”

Confused yet? 

Here’s what I would suggest

• Consider your use:  In higher moisture applications (e.g., kitchens), vertical (cross-cut) grain solid bamboo (as opposed to horizontal/flat grain that shows the bamboo’s nodes) and engineered products offer more stability.  In high traffic areas, choose the natural colour over caramelized, which can be up to 20% softer due to the carbonizing process used to create the colour.
• Consider where you live. Since the UK isn’t huge and so overland transport miles aren’t great, most of the transportation miles will be by ocean freighter.  In the USA (particularly where I used to live in Minnesota, which was about as far away from a major port as possible – ok, yes, there’s Duluth, but how much bamboo comes through Duluth?) requires many more overland miles.  Regardless, it might make more sense to source a locally grown and processed, and FSC certified, hard wood instead.
• If it’s important to you to buy locally, that does pretty much rule out bamboo.
• For indoor air quality reasons, seek bamboo made with (and installed with) low- or no-VOC adhesives to minimize off-gassing.
• The best eco-friendly colour options are ‘natural’ and the carbonized ‘caramel’ colour.  Avoid coloured bamboo (especially metallics).
• Solid planks have an eco advantage over engineered planks, which are combined with a less rapidly renewable wood (typically pine) as a substrate.
• Purchase from a quality supplier – the bamboo market has been flooded and it can be a case of you get what you pay for.
• If possible, select FSC certified bamboo from a manufacturer meeting ISO 9001 standards.

Sources: 

• “Bamboo Flooring”  Product News from BuildingGreen.com
• “Bamboo Flooring – Is it Really Treehugger Green?”  by Lloyd Alter, Treehugger.com
• “Is it OK to steal food from pandas?” by Lucy Siegle, Guardian.co.uk

Photo by uhltank.