Does Polyester Cause Cancer? Is It Toxic?

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What Exactly is Polyester, Anyway?

In chemistry, the term “polyester” refers to a category of polymers that can include both naturally-occurring and synthetic materials. For example, plants and bees both produce “polyesters” of different kinds.

However, natural polyester isn’t what most people are referring to when they use the term. Instead, we’re talking about fabric. And more specifically, a kind of synthetic fabric.

Despite the fact that we think of it as a textile, polyester fabric is still a kind of plastic. It’s made when petroleum is refined and combined with water and various processing chemicals to make a resin that’s woven into a plastic textile.

You’re probably well aware that polyester is one of the most common types of fabric used in clothing today. It’s cheap, versatile, and relatively easy to make. According to a 2022 Textile Exchange report, polyester accounted for about 54% of total global fiber production in 2021, making it the most widely-used textile.

According to the same report, “around 30-60% of polyester fibers are used for apparel, 20-35% are used for home textiles, and the remaining part for various other applications.”

The technical term for polyester is polyethylene terephthalate (aka PET). It was originally introduced in the early 1940s and then brought to the masses over the following decade by the DuPont. (Yes, that’s the now-infamous chemical giant that has poisoned the water for multiple communities, like in West Virginia and North Carolina.)

Despite the fact that it literally has “phthalate” in the name, polyester (PET) isn’t actually a phthalate itself. That being said, phthalates can be added to PET to make a finished product. PET can also have endocrine disrupting effects from other chemicals such as antimony compounds, but we’ll get to that in a minute.

The Pros & Cons of Polyester Fabric

From both a consumer and environmental standpoint, polyester definitely has it’s upsides and downsides:

Is Polyester Toxic?

Before we answer dive deeper into the potentially harmful chemicals used in polyester manufacturing, allow me to make a quick note about semantics.

The question I was asked was: “Does polyester cause cancer?” One way to answer that question would be: there have not been any scientific studies (that I know of) that have looked at a direct cause-and-effect relationship between polyester and cancer.

Therefore, the real question we’re answering here is a little bit different. It’s: “Does polyester contain carcinogens (and/or other toxic chemicals)?”

The question of whether polyester causes cancer can be a scary one, especially considering that almost everyone has polyester somewhere in their home… Maybe even a lot of it!

My goal is never to scare you. Rather, the goal is to arm you with information to take steps toward the healthiest life for you and your family. While throwing out your entire wardrobe and buying all new clothings may not be wise or realistic, you may simply choose a different fabric the next time you’re in need of some fresh t-shirts or a new undies. You might choose to be more strategic about where and when you do and don’t use synthetic fabrics in your life based on your own budget, skin sensitivities, preferences, etc. Always remember to just take it one step at a time and do the best you can.

Now, let’s look at the different health concerns that may arrive when it comes to polyester and its common chemical additives:

Cancer

Polyester can include several different chemicals that are known carcinogens. Some of these are used to produce the actual fabric, while others may be added as finishes.

• Antimony & Its Compounds: Antimony is a heavy metal that’s used to produce polyester itself, and it’s also used in the fabric dyeing process. In a 2013 clothing investigation, Greenpeace found antimony in all of the polyester garments tested. Trivalent antimony is one of the more toxic antimony compounds and is classified as a probable human carcinogen by the IARC. Trivalent antimony is present in antimony trioxide, which is commonly used as a catalyst in the manufacturing of PET.

• Azobenzene Dyes: More commonly referred to as “azo dyes,” azobenzene colorants can be used on any kind of fabric, whether that’s polyester, cotton, or something else. Sometimes, the dyes themselves are carcinogenic, while other times, their metabolites (called aromatic amines) are what makes them carcinogenic. The European Union has banned many azo dyes and aromatic compounds, and California has also added them to the Prop 65 list.

• Formaldehyde: Formaldehyde is a known carcinogen. It’s used in clothing (made from polyester as well as other kinds of fabric) for many different reasons, including to prevent things like wrinkling, shrinking, staining, static cling, and mold/mildew growth during shipping. It’s also used to hold shapes and colors. If you’ve ever pulled a garment out of a box and experienced a strong “chemical” smell, there’s a good chance that was formaldehyde.

• PFAS: PFAS are those “forever chemicals” that make things water-resistant. They’re often added as a fabric finish, and they can be added to polyester as well as cotton or pretty much any other type of textile. They’re known to increase the risk of various kinds of cancer.

• BPA: Linked to a few differnet kinds of cancer, including breast and prostate, BPA has been found in several clothing investigations done by the Center for Environmental Health. Specifically, they’ve tested socks, sports bras, and athletic shirts from a variety of brands. In all three cases, they found BPA in the garments made from polyester and spandex and did not find BPA in the items made predominantly out of cotton.

• Chlorobenzenes and Chlorotoluenes: These are used for various purposes, including as solvents, dye-carriers, biocides, and as chemical intermediates. They’re more likely to be found in polyester and polyester blend fabrics rather than more natural textiles like cotton or linen. There are different types of cholorobenzens and some of them are listed as “possibly carcinogenic to humans” by the IARC. There are restrictions on chlorobenzene levels in the E.U.

Fertility

It turns out that scientists have actually been studying the link between polyester and fertility for decades. Back in 1993, one study put polyester and cotton underwear on dogs for a full 24 months and measured their sperm count, semen character, testicular temperature, and hormones. The study found significantly decreased sperm and fertility health in the dogs that wore the polyester underwear, while the dogs that wore cotton underwear and the dogs that didn’t wear any underwear at all did not have any significant change. The authors didn’t give a specific reason for what exactly it was in the polyester that was causing the harm.

The good news from this study is that for the majority of the dogs that wore the polyester underwear, they were actually able to gradually reverse the negative effects on sperm quality simply by taking the underwear off. This suggests that switching your underwear to a more natural fabric can potentially make a real difference in fertility (especially for the guys).

Now, let’s look at some of the specific chemicals in polyester that may contribute to decreased fertility or related reproductive problems:

• BPA: BPA is a known endocrine disruptor, linked to things like reduced sperm count, recurring miscarriages, and birth defects. One of the more concerning aspects about BPA is that it’s been found to have negative effects even at very low levels, going against the traditional belief that “the dose makes the poison.” We know that BPA can be absorbed through the skin from touching paper receipts, so it’s reasonable to assume that it can likely be absorbed into the skin from textiles as well.

• Lead: Lead in polyester (and other clothing) often comes from the ink, as was the case in a 2022 recall of kids’ Disney clothes. In adults, lead can cause reproductive harm and miscarriage, as well as other negative health effects. Of course, most people are also aware that lead comes with serious risks to the longterm neurological health of developing babies and children, too.

• PFAS: Again, PFAS can be added to polyester and other fabrics to make them water and stain resistant. This class of chemicals is known to disrupt healthy hormone function and can negatively affect things like thyroid health, pregnancy outcomes, fetal development, the timing of puberty, and more.

• NPEs: Also known endocrine disruptors, nonylphenol ethoxylates (NPEs) are commonly used as surfactants or emulsifiers in the textile manufacturing process. They’re used for dye dispersement, pattern printing, yarn spinning, leather/wool scouring, fabric softening, and more. This can be the case for polyester as well as other kinds of fabrics. In 2012, a Greenpeace report found NPEs in about two thirds of the garments they tested. A few years after that, the E.U. banned NPEs from textile imports. (There is not currently a ban in the U.S.)

• Chlorobenzenes: At least one specific chemical in this class (Hexachlorobenzene, or HCB) is a known endocrine disruptor. This chemical is restricted in some places.

Skin Allergies & Sensitivities

Those with sensitive skin, eczema, or a polyester allergy (aka textile contact dermatitis) may be the most familiar with the acute effects of polyester can cause. Symptoms can include things like:

• rashes or hives
• redness
• itching or burning
• skin tenderness
• skin feeling warmer than usual

It can be quite difficult to pinpoint exactly what it is in the fabric that is actually causing the reaction. Is it the fabric itself, one of the finishes that’s been added to the textile, or a combination of multiple things?

Many of the chemicals we’ve already talked about are also associated with skin problems:

• Trivalent antimony is known to cause dermatitis.

• Azo dyes cause adverse skin reactions. And since they are water-soluble, symptoms may worsen when you sweat in azo-dyed clothing.

• Formaldehyde in textiles has been known to cause contact dermatitis.

Despite the fact that azo dyes and formaldehyde can technically be added to all kinds of fabrics, their effects may be worse for polyester and other synthetics because of the fact that it’s not breathable. When you wear polyester, you don’t get a lot of air flow, which can cause increased sweating, rubbing, and chafing. All of this can lead to a downward spiral of skin irritation for those who are prone to it.

Respiratory Health

Many times, if something can irritate the skin and eyes then it can also irritate the ears, nose, throat, and lungs. In the case of polyester fabrics:

• Antimony can cause short-term effects via inhalation, including skin and eye irritation. Meanwhile, longterm concerns can include inflammation of the lungs, chronic bronchitis, chronic emphysema, and more. People who work in polyester manufacturing (and other industrial settings) are more like to experience these symptoms.

• Similarly, formaldehyde can also cause acute reactions, including lightheadedness; watery or red eyes; burning in the throat; or coughing.

Immune Health & Inflammation

Polyester and the chemicals added to it can also cause, exacerbate, or contribute to decreased immune function, autoimmune disorder, and general inflammation in the body. For example:

• Antimony has been found to interfere with proper functioning of the immune system and can also cause problems with the lungs, heart, and stomach in industrial settings.

• Formaldehyde in haircare products has been linked to an increased risk of autoimmune disease.

• PFAS can also cause inflammatory diseases like ulcerative colitis and cause general immune system dysfunction.

• Likewise, BPA is also linked with inflammatory bowel disease (including ulcerative colitis and Crohn’s disease) as well various other serious health concerns like heart disease and mental illness.

• Chlorobenzenes can negatively affect the central nervous system (as well as the liver and thyroid).

• Other environmental toxins have been implicated in autoimmunity as well. Some of these chemicals can be found in clothing, including heavy metals, solvents, and endocrine disruptors.

The Environment

Of course, environmental health and human health usually go hand in hand. But when these chemicals are released into the environment, they can also cause harm for plants, animals, insects, and ecosystems as a whole. Chemicals can be released into the air and/or dumped into waterways during the manufacturing process, or they can gradually break down and wear off into the environment as we wash and wear them.

Some of the chemicals used in polyester fabrics, like PFAS, NPEs, and chlorobenzenes are also bioaccumulative, which means that rather than breaking down, they just keep building up in the environment over time.

Is polyester toxic to sleep on?

All of the above info about polyester clothing can also be said of your bed sheets as well. While it’s hard to say for sure, there could be toxic antimony from polyester manufacturing and/or other chemicals like azo dyes or BPA in your bedding.

Considering that we spend about a third of our lives on our bed sheets (and that our bodies do a lot of recovering and repairing during sleep), investing in healthier bed sheets can be a good idea. Of course, this is especially true if you have a skin condition that may be more acutely affected by prolonged contact with polyester.

You may not need to run out and buy new sheets immediately, but the next time you’re in need of a bedding refresh, go for organic cotton, linen, or TENCEL (for a cooling effect). Here are some great brands to check out.

Does polyester leach phthalates?

Even though the official name of polyester (polyethylene terephthalate) has the word “phthalate” in it, polyester in its raw form doesn’t actually have phthalates in it. That being said, phthalates can be added to products later in the production process, like for coloring or or adding those “plastic-y” logos and images you find on t-shirts.

A few investigations in recent years have found elevated levels of phthalates in jeans, raincoats, vegan leather, infant cotton clothing, and more.

Phthalates are more likely to leach out of products at warmer temperatures. So although there haven’t been any studies done yet (that I know of) which have measured the specific amount of phthalates that leach from clothing while it’s worn, it is reasonable to assume that there may be at least some leaching that occurs while the clothing is against your warm skin, and perhaps even more while working out or when in a hot climate.

What about cotton-polyester blends?

Many of the above problems can also be said of fabric blends. For example, manufacturers will often add cotton to polyester to give it a more “natural” and less “synthetic” feel, especially for bedding. But considering that cotton is more likely to wrinkle and shrink, this is even more reason for manufactures to add formaldehyde to the fabrics. 

Therefore, cotton-polyester blends aren’t necessarily more or less toxic than something that’s 100% polyester. At the end of the day, it just depends on the exact makeup of the blend, how it’s processed, and what’s added to it.

Virgin vs. Recycled Polyester: Is There a Difference in Toxicity?

In an effort to reduce the amount of plastic waste that ends up in waterways and landfills, many brands are switching to recycled fabrics for their synthetic clothing. Using post consumer plastic bottles to make recycled polyester, for example, is common practice these days.

From one point of view, this is a good move. It means less plastic pollution, less need for virgin plastics, and more circularity of resources as a whole.

But what about from a human health standpoint?

Well, the short answer is that clothing made from recycled polyester probably isn’t any less toxic than clothing made from virgin polyester. There’s some indication that products like water bottles made from recycled plastic may be even worse than those made from virgin plastic.

Plus, manufacturers don’t always know what’s even in the plastics they’re recycling. So for example, even if they don’t add BPA into their product, they may not be aware that the material they’re recycling already had BPA in it.

Unfortunately, there hasn’t been a whole lot of testing in this arena, especially for clothing. In the BPA investigation by CEH, they didn’t indicate how many of the products they tested were made from recycled fabrics, but considering they tested over 100 different brands, it would be reasonable to believe that some of the brands used virgin materials and some used recycled.

How to Strategically Minimize the Polyester Fabrics Around You

It’s probably not realistic to take ALL of the polyester out of your wardrobe, but here are some tips to help you prioritize and strategize:

• As you buy new clothes and bedding, slowly transition to natural fabrics like organic cotton, linen, and hemp. Don’t try and replace your entire wardrobe and bedding all overnight.

• Of course, those who have skin problems, autoimmune disorders, chemical sensitivities, or other conditions may want to put more urgency behind the switch to natural fibers, in case reducing contact with polyester textiles will make a more immediate difference.

• When deciding which categories to tackle first, prioritize the fabrics that:
  • Are against your skin more (like underwear)
  • You sweat in (like activewear)
  • You wear the most (whether that’s workwear, sleepwear, or something else)

• For both synthetic and natural/organic materials, look for third-party certifications. Labels like OEKO-TEX, bluesign, and GOTS restrict and/or minimize many of the chemicals addressed here. These certifications aren’t perfect, but they definitely help.

• Be strategic about the items you DO buy that are made from polyester. For example, a raincoat made from polyester but free from PFAS is probably a better option than a raincoat that’s made from organic cotton but then treated with a toxic PFAS layer to make it waterproof. Same with things like upholstered furniture.

• Try to avoid buying “performance” fabrics that have labels like “wrinkle-resistant,” “iron-free,” “stain-proof,” etc.

• If you can, change out of sweaty synthetic clothes after you exercise in them.

• When you do wear synthetic material, make sure it fits properly in order to reduce friction that could cause extra skin irritation.

• Wash new clothes before wearing them.

• For children’s pajamas, buy tight-fitting PJs and look for a tag that says the garment is NOT treated with flame retardant chemicals.

• Keep in mind that there are some items that you just aren’t going to be able to find in a non-synthetic material. Take swimwear and Halloween costumes, for example. For these products, you may just have to make the best decision you can (even if it’s not ideal) and try not to stress too much. You still want to enjoy life — and that includes going to the beach and taking the little ones trick-or-treating!

For more tips on how to decrease the environmental toxins in your life, stay up to date on the latest toxin-related headlines, and more, sign up for Filtered Fridays.