Polyester is a very popular fabric choice – it is, in fact, the most popular of all the synthetics. Because it can often have a synthetic feel, it is often blended with natural fibers, to get the benefit of natural fibers which breathe and feel good next to the skin, coupled with polyester’s durability, water repellence and wrinkle resistance. Most sheets sold in the United States, for instance, are cotton/poly blends.
It is also used in the manufacture of all kinds of clothing and sportswear – not to mention diapers, sanitary pads, mattresses, upholstery, curtains and carpet. If you look at labels, you might be surprised just how many products in your life are made from polyester fibers.
So what is this polyester that we live intimately with each day?
At this point, I think it would be good to have a basic primer on polyester production, and I’ve unabashedly lifted a great discussion from Marc Pehkonen and Lori Taylor, writing in their website diaperpin.com:
Basic polymer chemistry isn’t too complicated, but for most people the manufacture of the plastics that surround us is a mystery, which no doubt suits the chemical producers very well. A working knowledge of the principles involved here will
make us more informed users.
Polyester is only one compound in a class of petroleum-derived substances known as polymers. Thus, polyester (in common with most polymers) begins its life in our time as crude oil. Crude oil is a cocktail of components that can be separated by industrial distillation. Gasoline is one of these components, and the precursors of polymers such as polyethylene are also present.
Polymers are made by chemically reacting a lot of little molecules together to make one long molecule, like a string of beads. The little molecules are called monomers and the long molecules are called polymers.
O + O + O + . . . makes OOOOOOOOOOOOOOOO
Depending on which polymer is required, different monomers are chosen. Ethylene, the monomer for polyethylene, is obtained directly from the distillation of crude oil; other monomers have to be synthesized from more complex petroleum derivatives, and the path to these monomers can be several steps long. The path for polyester, which is made by reacting ethylene glycol and terephthalic acid, is shown below. Key properties of the intermediate materials are also shown.
The polymers themselves are theoretically quite unreactive and therefore not particularly harmful, but this is most certainly not true of the monomers. Chemical companies usually make a big deal of how stable and unreactive the polymers are, but that’s not what we should be interested in. We need to ask, what about the monomers? How unreactive are they?
We need to ask these questions because a small proportion of the monomer will never be converted into polymer. It just gets trapped in between the polymer chains, like peas in spaghetti. Over time this unreacted monomer can escape, either by off-gassing into the atmosphere if the initial monomers were volatile, or by dissolving into water if the monomers were soluble. Because these monomers are so toxic, it takes very small quantities to be harmful to humans, so it is important to know about the monomers before you put the polymers next to your skin or in your home. Since your skin is usually moist,
any water-borne monomers will find an easy route into your body.
Polyester is the terminal product in a chain of very reactive and toxic precursors. Most are carcinogens; all are poisonous. And even if none of these chemicals remain entrapped in the final polyester structure (which they most likely do), the manufacturing process requires workers and our environment to be exposed to some or all of the chemicals shown in the flowchart above. There is no doubt that the manufacture of polyester is an environmental and public health burden
that we would be better off without.
What does all of that mean in terms of our health? Just by looking at one type of cancer, we can see how our lives are being changed by plastic use:
- The connection between plastic and breast cancer was first discovered in 1987 at Tufts Medical School in Boston by
research scientists Dr. Ana Soto and Dr. Carlos Sonnenschein. In the midst of their experiments on cancer cell growth, endocrine-disrupting chemicals leached from plastic test tubes into the researcher’s laboratory experiment, causing a rampant proliferation of breast cancer cells. Their findings were published in Environmental Health Perspectives (1991).
- Spanish researchers, Fatima and Nicolas Olea, tested metal food cans that were lined with plastic. The cans were also found to be leaching hormone disrupting chemicals in 50% of the cans tested. The levels of contamination were twenty-seven times more than the amount a Stanford team reported was enough to make breast cancer cells proliferate. Reportedly, 85% of the food cans in the United States are lined with plastic. The Oleas reported their findings in Environmental Health Perspectives (1995).
- Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. 
These studies support claims that plastics are simply not good for us – prior to 1940, breast cancer was relatively rare; today it affects 1 in 11 women. We’re not saying that plastics alone are responsible for this increase, but to think that they don’t contribute to it is, we think, willful denial. After all, gravity existed before Newton’s father planted the apple tree and the world was just as round before Columbus was born.
Polyester fabric is soft, smooth, supple – yet still a plastic. It contributes to our body burden in ways that we are just beginning to understand. And because polyester is highly flammable, it is often treated with a flame retardant, increasing the toxic load. So if you think that you’ve lived this long being exposed to these chemicals and haven’t had a problem, remember that the human body can only withstand so much toxic load – and that the endocrine disrupting chemicals which don’t seem to bother you may be affecting generations to come.
Agin, this is a blog which is supposed to cover topics in textiles: polyester is by far the most popular fabric in the United States. Even if made of recycled yarns, the toxic monomers are still the building blocks of the fibers. And no mention is ever made of the processing chemicals used to dye and finish the polyester fabrics, which as we know contain some of the chemicals which are most damaging to human health.
Why does a specifier make the decision to use polyester – or another synthetic – when all the data points to this fiber as being detrimental to the health and well being of the occupants? Why is there not a concerted cry for safe processing chemicals at the very least?
 Sax, Leonard, “Polyethylene Terephthalate may Yield Endocrine Disruptors”,
Environmental Health Perspectives, April 2010, 118 (4): 445-448
31 thoughts on “Polyester and our health”
As usual, a great article, thank you. The diagram simplifies the chemistry brilliantly – surely sufficient to convert the skeptics. Once again, oil is problem, or rather, the greed of those using it instead of less dangerous products.
Great article but contains faulse reference (number 2) to the source that has nothing common to the subject
Thanks so much for catching that! I’ve updated with correct reference.
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Very interesting article, especialy the monomer/ polymer explanation.. Working with recycled PET a lot, but it definitely made us thinking. A step to the side: how does the above translate to the use of bio-based yarns, eg PLA? Does this have the same chemical limitations compared to eg cotton?
We did a series of blog posts on bio polymers, one pertaining especially to PLA (“Biopolymers and polylactic acid (PLA) – or rather Ingeo): https://oecotextiles.wordpress.com/2011/04/27/biopolymers-and-polylactic-acid-pla-or-rather-ingeo/; also see the series of posts on general topic of biopolymers and the new bioeconomy – you can search on the right hand side of the page for “biopolymers”. They ran in April and May of 2012.
Totally missed that one, thanks a lot for the in-depth information on your Blog and keep up the good work!
My son is wearing school pants that are 100% cotton but treated for stains and wrinkles and a poli cotton blend that is not treated. Both are not ideal but which is the least of the 2 evils?Thank you Lalita
Hi Lalita I’m not qualified to split those kinds of hairs – but sure sounds like a toss up to me.
Finally, I have found a very informative source, going deep into the issues! thank you. I am wondering about used polyester clothing…I’m wondering about the off-gasing life of the monomers…if one is on a budget, and conscious of the garment/fabric industry and all it’s evils, then used clothing seems to be a good option. But I”d like to know more about the life-span of the “fiber” and the better or worseness, if you will, of a piece of clothing that has already “off-gased” a signifcant amount of monomers. Lesser of many evils? thank you!
Hi Azula: The real chemical of concern in polyester is antimony, and it’s pretty much locked in the polymer. It is not volatile, so no off gassing. But the problem with using synthetic fibers of any kind is that they don’t readily decompose, sitting in landfills for a very long time and leaching the chemicals of concern into our soil and groundwater. But I think reusing an existing garment/fabric is a good idea since it’s destined for the landfill either way – and you’re doing your part to postpone that eventuality!
Hello O Ecotextiles, first of all, thank you for this brilliant and clearly written article! I am hoping to create cushions and would like to offer them with a washable filling (I have a house dust mite allergy so am mindful of people like myself needing to wash the insert). I have come across one (!) company doing recycled PET fillings, in Australia. I would have thought this is the best practice solution. Can you advise on any alternatives that are washable, eco-friendly in production and non-toxic in use? Thank you!
We have heard that kapok might fit the bill – sourced from the kapok tree (Ceiba Pentandra), it’s a batting that has a silky feel. From what we hear, nothing is done to it, so it’s entirely non-toxic and also hypo-allergenic It can be washed. These washing instructions are from Nest Bedding: WASHING KAPOK PILLOW – Kapok was originally used in life jacket as it is water resistant so when you wash in other than a front loader, you need to fill washer and submerge. HEAVY FILL NOT RECOMMEND FOR MACHINE WASHING.
DRY KAPOK PILLOW – Some washers cause the kapok to clump – before putting in dryer, through the cover, pull the kapok apart to allow the heat from the dryer to get to all the kapok. After about 30 minutes, do this same process again if there are any clumps. HEAVY FILL NOT RECOMMENDED FOR DRYER.
Kapok is an allergen for some asthma sufferers though, so be aware of that.
Thank you for your wonderful and informative blog. Do you have any suggestions on materials to use for blackout Roman blinds? Polyester is just so cheap (and at least it’s not coated with PVC). I understand we bear the cost of plastics in other ways, though. Modern life is complicated!
Hi Paula: Yes modern life is complicated and plastics are part of modern life, in fact we depend on plastic for so many things. It’s just that we’re overwhelmed by the quantity so it might be nice to limit our exposure! One suggestion we have is to interline your Roman Blinds with a black fabric (cotton or natural fiber, GOTS preferably).
Any comment on environmental impacts of marine microfibre plastic pollution from polyester? Combined with human health concerns this doesn’t look too good for polyester and recycled polyester textiles.
I thought we had done a blog on that subject, but I couldn’t find it. Should revisit the topic soon – especially since this microfiber pollution is linked directly to fabrics.
This article helps me understand why I can’t wear polyester, or nylon for that matter. As soon as I put on a polyester garment I begin to black out from heat sensation. Every summer I have problems looking for suitable clothes. I have felt a bit of a mess in creased linens and cottons at important events,but well and very alive! Just a week ago I tried on a dress in a shop , (a size larger than the previous one), handed to me by an assistant. I had a real panic to get out of it fast; a hot day in a hot changing room, I had to sit down to recover! People smile patiently and maybe think I exaggerate but I am finding a whole number of fellow sufferers too. Thank you for the information.
I noticed in this article you are very anti polyester, but on another article comments, you stated “There is, truly, little to fear from the polyester itself” Which seems a little contradictory to this post.
You’re right – I’m no fan of polyester. Though the fibers themselves might pose little in the way of health risks (at this point in time, though not much research has been done to date and I’m sorry I didn’t explain the statement about polyester fibers themselves posing little risk), if those fibers were processed conventionally then they’d still be full of the chemicals that are used in textile processing which have been proven to be bad for our health. But the real reason I’m no fan of polyester is that it’s just another plastic, and we’re drowning in plastic pollution. The chemicals used to produce the polyester are some of the most toxic known, and just to get rid of the sludge from polyester production is a major headache. We use our dwindling fossil fuels to produce the stuff, and then the chemicals leach into our groundwater where it transitions to tuna and salmon and other fish that we then eat. As I said in an earlier blog post: Polyester is the terminal product in a chain of very reactive and toxic precursors. Most are carcinogens; all are poisonous. And even if none of these chemicals remain entrapped in the final polyester structure (jury’s out on this), the manufacturing process requires workers and our environment to be exposed to some or all of the chemicals. The production of the stuff is an environmental and public health burden. And what about the Great Pacific Garbage Patch, or the fact that scientists are finding that the sand on beaches around the world is made up of plastic fibers from textiles. Polyester is just another plastic, it does not biodegrade, it poisons the food chain, and it affects the health of humans and wildlife.
I have an expensive microfiber polyester bed sheets and pillow sheets which are oeko tex certified. Would you suggest to throw them out? What are the dangers of using them? Is it possible that I would be breathing or eating microplastic, plastc dust and little fabric threads if i sleep on them? Thanks!
You will be abrading microscopic pieces of the plastic fiber and ingesting/inhaling them. The question is: Is that a concern?
Your sheets most likely have an Oeko-Tex 100 certification (Oeko-Tex has promulgated many standards), which means that they are free of residual chemicals of concern. If they were not certified, we’d suggest that you put getting new sheets on your things to do list.
But you have sheets that are not full of those residual process or finishing chemicals, so the question is: Are the tiny plastic fibers you will be ingesting/inhaling a concern? The answer is, currently, nobody knows.
If the microfibers are either acrylic or polyester, the two most frequently used in microfiber production, they are chemically inert once produced – for the most part. But is there another deleterious health effect from just the presence of those strands in our bodies – ignoring chemical breakdown and the absence of free chemicals of known suspicion? Unknown.
We don’t mean to scare you by inferring something about something unknown. You can most likely keep using them with little concern. The amount of fiber you will be abrading and ingesting is most likely less than the amount of plastic you are breathing in the air.
There are LOTS of very important reasons to STOP or severely limit our purchases of synthetic fiber fabrics, but the fibers without the added horrid processing chemicals are pretty much chemically inert probably and the tiny strands are de minimus that you would be ingesting.
When you buy fabric next, steer away from synthetic fibers, Oeko-Tex 100 certified or not.
One of the disadvantages of the Oeko-Tex 100 standard is that they do certify synthetic fiber fabrics.
If I were in your position, I would replace them as soon as my budget allowed, but I wouldn’t be feeling, say, the same kind of pressure of getting rid of something with FR or stain repellent finishes on it.
so, I’ve recently started taking an old 100% polyester IKEA Gosig golden retriever stuffed animal into my bed to sleep with. I’ve been having really terrible sleep disturbances, and it’s one of the few things I’ve found that actually helps me sleep. But now I’m kind of scared. Is it dangerous to have this in my bed, possibly touching bare skin on my arms for 8 hours a night? I really hope I don’t have to give it up, because it’ll mean going back to square one with my sleep issues (the softness, size, and shape are perfect, and it’d probably be difficult to find another stuffed animal that’s just right). But if it’s likely to cause cancer or something, I’d need to do it anyway. I’m totally on board for the numerous reasons to avoid polyester in the future—but I’m fairly worried about what to do about this specific existing item. I really appreciate any info or perspective on the magnitude of the danger here!
Hi A; You are probably fine. We are researching this issue right now. But we think the exposure to monomers from poly degradation happens at such a slow rate that the issue is de minimus (not of great concern). Other synthetics, we’re not as sanguine about. That said, since your stuffed animal is not Oeko-Tex 100 or GOTS certified, none of us can be sure that your animal does not contain residual chemicals of concern. But it is NOT one of the products that gets the REALLY nasty list of chemicals added to it pretty routinely – and IKEA also tends to have a better record of not using the worst additives.
We have just learned of this issue and my daughter is frantic. She has packed up probably half of her 4 month old babies cloths and she has now found that most of her clothes have polyester in them. She cannot really afford to replace all of her clothes but is determined in case it hurts her son somehow. What are your thoughts and is it necessary. If this is so bad why on earth is it allowed to be used especially in babies clothing. She is also throwing out her bedding, cushions, pillows and curtains. Is this necessary
I personally do not think your daughter is being unreasonable UNLESS she can find or determine that the items are either Oeko-Tex 100 or, better, GOTS certified. She does not need lots of items. Some of the items might be Oeko-Tex 100 certified. Oeko-Tex does certify synthetics. So, in the Hohenstein Institute’s opinion (They are reliable), synthetics with no added chemicals are safe to use. We cannot support our unease with the claims of the “safety” of the use of the synthetic polymers themselves. We have found many exceptions to the claims (do NOT buy vinyl or polyurethane or SBR or any soft plastic)– although it appears as if most of the studies are about chemicals added to the synthetic polymers after they are created, not necessarily the polymers themselves.
One of the major problems, apart from the safety of use of the unadulterated synthetic yarn is that many chemicals are added to the synthetic melt – and NONE of them are legally required to be revealed. If the clothes or sheets claim wrinkle resistance or stain resistance, etc, please do throw them out immediately. I would not want them around a 4 year old. Or an 84 year old, although 4 year olds are more sensitive. As I said in the answer to the question from May 7, 2022, just above, we are researching this issue again right now. The industry maintains strenuously that synthetics polymers, once produced, and before degradation in a landfill at end of life, are “inert” and safe to use. They maintain that the degradation during use if of “de minimus” concern. This is generally accepted but there are no studies we have found that prove it. The safety of use is mostly just assumed and not proven. Go to any toxicology database and look at, for instance, polyurethane, which is NOT inert, and all of categories of toxicology report NO DATA, NO DATA, not data that proves that the synthetic is actually safe.
I personally do not think your daughter is being unreasonable UNLESS she can find or determine that the items are either Oeko-Tex 100 or, better, GOTS certified. She does not need lots of items. We have a surplus of some kinds of fabric which I would be happy to ship for the cost of shipping if this creates a hardship. We sell on a sliding scale, too.
Oh, and you asked:
If this is so bad why on earth is it allowed to be used especially in babies clothing.
We have many blogs on this sad state of affairs. The US government does not regulate the chemical industry or chemicals in products well. If it were not for Japan and the European Union, we would not have much toxicology information on common synthetic chemicals.
Here is a good blog post to start with:
in which we state, and it remains true:
What does this mean? It means that the United States has basically no protection for consumers in terms of textiles.