Synthetic fibers are the most popular fibers in the world with 65% of world production of fibers being synthetic and 35% natural fibers. (1) Fully 70% of that synthetic fiber production is polyester. There are many different types of polyester, but the type most often produced for use in textiles is polyethylene terephthalate, abbreviated PET. Used in a fabric, it’s most often referred to as “polyester” or “poly”. It is very cheap to produce, and that’s a primary driver for its use in the textile industry.
The majority of the world’s PET production – about 60% – is used to make fibers for textiles; and about 30% is used to make bottles. Annual PET production requires 104 million barrels of oil – that’s 70 million barrels just to produce the virgin polyester used in fabrics.(2) That means most polyester – 70 million barrels worth – is manufactured specifically to be made into fibers, NOT bottles, as many people think. Of the 30% of PET which is used to make bottles, only a tiny fraction is recycled into fibers. But the idea of using recycled bottles – “diverting waste from landfills” – and turning it into fibers has caught the public’s imagination. There are many reasons why using recycled polyester (often called rPET) is not a good choice given our climate crisis, but today’s post is concentrating on only one aspect of polyester: the fact that antimony is used as a catalyst to create PET. We will explore what that means.
Antimony is present in 80 – 85% of all virgin PET. Antimony is a carcinogen, and toxic to the heart, lungs, liver and skin. Long term inhalation causes chronic bronchitis and emphysema. The industry will say that although antimony is used as a catalyst in the production process, it is “locked” into the finished polymer, and not a concern to human health. And that’s correct: antimony used in the production of PET fibers becomes chemically bound to the PET polymer so your PET fabric does contain antimony but it isn’t available to your living system. (2)
But wait! Antimony is leached from the fibers during the high temperature dyeing process. The antimony that leaches from the fibers is expelled with the wastewater into our rivers (unless the fabric is woven at a mill which treats its wastewater). In fact, as much as 175ppm of antimony can be leached from the fiber during the dyeing process. This seemingly insignificant amount translates into a burden on water treatment facilities when multiplied by 19 million lbs each year – and it’s still a hazardous waste when precipitated out during treatment. Countries that can afford technologies that precipitate the metals out of the solution are left with a hazardous sludge that must then be disposed of in a properly managed landfill or incinerator operations. Countries who cannot or who are unwilling to employ these end-of-pipe treatments release antimony along with a host of other dangerous substances to open waters.
But what about the antimony that remains in the PET fabric? We do know that antimony leaches from PET bottles into the water or soda inside the bottles. The US Agency for Toxic Substances and Disease Registry says that the antimony in fabric is very tightly bound and does not expose people to antimony, (3) as I mentioned earlier. So if you want to take the government’s word for it, antimony in PET is not a problem for human health – at least directly in terms of exposure from fabrics which contain antimony. (Toxics crusader William McDonough has been on antimony’s case for years, however, and takes a much less sanguine view of antimony. (4) )
Antimony is just not a nice thing to be eating or drinking, and wearing it probably won’t hurt you, but the problem comes up during the production process – is it released into our environment? Recycling PET is a high temperature process, which creates wastewater tainted with antimony trioxide – and the dyeing process for recycled PET is problematic as I mentioned in an earlier post. Another problem occurs when the PET (recycled or virgin) is finally incinerated at the landfill – because then the antimony is released as a gas (antimony trioxide). Antimony trioxide has been classified as a carcinogen in the state of California since 1990, by various agencies in the U.S. (such as OSHA, ACGIH and IARC) and in the European Union. And the sludge produced during PET production (40 million pounds in the U.S. alone) when incinerated creates 800,000 lbs of fly ash which contains antimony, arsenic and other metals used during production.(5)
Designers are in love with polyesters because they’re so durable – and cheap (don’t forget cheap!). So they’re used a lot for public spaces. Abrasion results are a function not only of the fiber but also the construction of the fabric, and cotton and hemp can be designed to be very durable, but they will never achieve the same abrasion results that some polyesters have achieved – like 1,000,000 rubs. In the residential market, I would think most people wouldn’t want a fabric to last that long – I’ve noticed sofas which people leave on the streets with “free” signs on them, and never once did I notice that the sofa was suffering from fabric degredation! The “free” sofa just had to go because it was out of style, or stained, or something – I mean, have you even replaced a piece of furniture because the fabric had actually worn out? Hemp linens have been known to last for generations.
But I digress. Synthetic fibers can do many things that make our lives easier, and in many ways they’re the true miracle fibers. I think there will always be a place for (organic) natural fibers, which are comfortable and soothing next to human skin. And they certainly have that cachet: doesn’t silk damask sound better than Ultrasuede? The versatile synthetics have a place in our textile set – but I think the current crop of synthetics must be changed so the toxic inputs are removed and the nonsustainable feedstock (oil) is replaced. I have great hope for the biobased polymer research going on, because the next generation of miracle fibers just might come from sustainable sources.
(1) “New Approach of Synthetic Fibers Industry”, Textile Exchange, http://www.teonline.com/articles/2009/01/new-approach-of-synthetic-fibe.html
(2) Polyester, Absolute Astronomy.com: http://www.absoluteastronomy.com/topics/Polyester and Pacific Institute, Energy Implications of Bottled Water, Gleick and Cooley, Feb 2009, http://www.pacinst.org/reports/bottled_water/index.htm)
(3) Shotyk, William, et al, “Contamination of Canadian and European Bottled waters with antimony from PET containers”, Journal of Environmental Monitoring, 2006. http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=EM&Year=2006&ManuscriptID=b517844b&Iss=2
(4) http://www.atsdr.cdc.gov/toxprofiles/phs23.html
(5) http://www.victor-innovatex.com/doc/sustainability.pdf
(3) http://www.greenatworkmag.com/gwsubaccess/02mayjun/eco.html
OEcotextiles 
If sportswear brands had to list the chemicals used to make their polyester based apparel, which also feature UV protection, moisture-wicking etc. Is there a definitive list of the chemicals they use?
If you live in the European Union, the new REACH legislation attempts to limit the use of around 2000 of the most egregious chemicals, many of which are used in fabrics. In 2005, the Norwegian Textile panel listed chemicals of concern in textiles and the German Environmental Protection Agency has been active in identifying chemicals of concern. But these are all piecemeal. In the United States, there are no regulations with regard to textiles regarding the prohibition of certain chemicals except the few identified by the Toxic Substances Control Act of 1976 – it’s actually the opposite: flame retardants must be applied to various products and to fabrics used in commercial interior spaces. And as to sportswear brands using finishes such as UV protection, etc. – these are usually branded products and the chemical composition is considered proprietary information. So manufacturers sometimes don’t even know what is in the moisture-wicking product they apply, just that it does what it says it does. If a manufacturer is concerned, they can begin to ask questions and push the chemical companies to formulate safer alternatives. But I have not seen a rush to do that on the part of the sportswear manufacturers, especially now since the products are becoming ever more sophisticated.
Thank you for your information. Would it be possible to compile a list of chemicals used in a typical ‘polyester’ based sports apparel shirt which included additional finishes such as moisture-wicking and UV protection? I’m sure many consumers would like to know this information. It seems highly unlikely that any sportswear brand will voluntary declare this information or be required to do so by listing ingredients / chemicals on their products / clothing.
I’m sure this would be useful, and we will eventually get to the point where we can study those issues – but since we don’t use those finishes we haven’t had the opportunity (the time!) to study them. First you’d need to find out the chemicals used to create the effect you are looking for – like the perflurocarbons which are in stain repellants or PBDEs in fire retardants. But often unless / until there is a major outcry about a particularly egregious chemical which may be contained in them, the manufacturers continue to use whatever they like in their “secret formulas” and there is as yet no way for us to find out what they may be, unless they choose to tell us. MSDS sheets are not really useful, even if you could get your hands on one, because they’re targeted to workers who use them in their working environments.
Considering how widespread these UV protection and moisture-wicking finishes are used in sportswear apparel. Probably talking millions of polyester based shirts being manufactured using these chemicals. There must be some studies and or some authority who knows which combination of chemicals are used in these processes. I appreciate they may not be hazardous to the consumer, but it would be nice to have the information rather than just a description. Thank you again for your help.
It is too bad that everything we buy is probably toxic to some degree and then, if on the slim chance it isn’t, the production probably resulted in a toxic workplace and toxic water and land and then, of course, the USE of so much water when water is a luxury. Unfortunately, these issues seem to be unimportant to the ones who have the power to make a change or maybe there are not enough of the ones in power who want to make a change.
It is becoming impossible to enjoy buying anything and yet, sometimes it is necessary.
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I just bought a Coleman tent that had a warning that it contains known carcinogens. After calling them I was told it was due to the polyester used in the fabric. The person on the phone assured me that unless I was consuming the fabric, I would be safe. But, still I wonder.
Hi Paula: You’ve just experienced something that we try to explain about the products that are being sold – the retail or customer service people know nothing! There is, truly, little to fear from the polyester itself – it is the processing of the polyester in which chemicals that are carcinogenic are introduced. It may be the dyes used, it may be the yarn texturizers (often BpA) in the polyester yarns, or it could be something else. But since there are over 2,000 chemicals used in textile processing it’s anybody’s guess what the carcinogenic chemical is. But if the tent came with a warning, something that manufacturers will try desperately to avoid, I would believe them.
Hi, I want to buy the Elf Star Bamboo Waterproof Pads for my baby. On amazon it states “the product is OEKO-TEX Standard 100 certified, and safe to sensitive skins, which is ideal for babies and senior citizens”
But it is made with 20% polyester. I’m confused about some things in these articles and was wondering if you could shed some light on this. Thanks so much for all the great info!
Hi Amarie: The goal of the Oeko-Tex fabric safety standard is to ensure that fabrics pose no risk to human health.
The Oeko-Tex Standard, in use since 1992, prohibits the same long list of chemicals that GOTS prohibits; but Oeko-Tex addresses nothing else about the production steps. For example, wastewater treatment is not required, nor are workers rights addressed. It is NOT an organic certification and products bearing this mark are not necessarily made from organically grown fibers – or from natural fibers at all. Plastic yarn (polyester, nylon, acrylic) is permitted, as long as the processing of those yarns is done without using any of the prohibited chemicals. Oeko-Tex is only concerned with the safety of the final product.