Is Our Clothing Toxic? It's More Complicated Than We Think

Google "toxic fabrics" and a host of sites will come up, some from as far back as 1993. Generally they list a number of synthetic fabrics (acrylic, nylon, polyester) along with rayon (which is made from chemically processed wood pulp) and make the case that all are bad because they are made from scary chemicals. Obviously, natural fibers such as cotton, hemp, wool, and linen are the way to go. Those are made from plants and sheep, not coal and petroleum derivatives.

The truth is more complicated than this. Your clothing is never made solely out of just cotton or polyester. Every single fabric has some form of processing. It may be preshunk cotton, or superwash merino. It may be bleached. It's almost always dyed. And nowadays clothing comes in all kinds of high-tech variations: UV protective, bug repellant, wrinkle-free, stain resistant, antimicrobial, and so on. Even pure cotton can be grown with pesticides.

These chemicals pose a myriad of concerns for the environment, both in the place of manufacture and due to chemicals released through washing. But what about the safety to the wearer?

The Basics: What Are Fabrics Made From?

If you look in your closet, you'll likely find a number of different natural and synthetic fibers. Over 60 percent of global fiber consumption is comprised of petroleum based synthetic fibers, although some may be used for textiles other than clothing (like rugs or rope). Comparatively, cotton makes up nearly a quarter of textile consumption, with wool making up about 1 percent, and other natural fibers (hemp, linen, etc) accounting for 5 percent. The remaining 6.6 percent are wood-based cellulose fibers (e.g. rayon).

Natural fibers come from either plants or animals. Plants used for clothing include cotton, hemp and flax. Animal fibers are more diverse, even if some, such as yak, remain uncommon. However, sheep are not the only animals who can provide high-quality fiber: alpacas, goats (cashmere and mohair), rabbits (angora), yaks, camels, llamas, and even the wild alpaca relative, the vicuña, provide fiber used for clothing. Silk is also a natural fiber, made from the cocoons of the mulberry silkworm. Other animal products used in clothing are hides (leather), feathers (down) and fur.

While humans have used natural fibers for millennia, rayon, which is made from wood fibers with synthetic processing, was invented in 1894, and the first fully synthetic fiber, nylon, was invented in the 1930s. Other wood-based fibers produced with synthetic processing include modal and bamboo. Fully synthetic fibers, generally made from petroleum or coal products, are acrylic, polyester and spandex.

Toxicology research into clothing focuses less on the fibers themselves and more on the chemicals used in processing the fibers. Even a simple cotton T-shirt requires numerous chemicals to bring it to market. The question for consumers is not only how safe are the chemicals used, but what are you willing to sacrifice and how much are you willing to spend in order to get the chemicals out of your closet? 

Chemicals Worth Dyeing For

Your clothes do not contain only cotton or rayon or polyester. They are also bleached and dyed. Dyeing also requires the use of a "mordant," a chemical that helps the dye adhere to the clothing. While natural dyes can be used along with a mordant like alum or cream of tartar, unless your clothing says otherwise, you can be almost certain natural dyes were not used.

Three different dye chemicals (or groups of chemicals) are of most concern. Azo dyes can release chemicals called aromatic amines when you wear them, and they can be absorbed into your body. There are hundreds of different azo dyes, and a large number of them can release aromatic amines. Some of these aromatic amines are known to be toxic (or as scientists put it, they are of "toxicological concern"), and others have never been assessed for toxicity. The main concerns are that these chemicals can cause cancer, and they also may be allergens. A 2014 study found that 17 percent of clothing samples contained aromatic amines "of high toxicological concern," including several that had them in higher levels than legally allowed in the European Union.

Second, quinoline is a chemical used in dying textiles that causes concern. According to another 2014 study, even though no human studies on their carcinogenicity are available, tests involving acute exposure of mice have demonstrated "quinoline and some of its methylated isomers to induce liver cancer." That study found that quinoline was found in polyester clothing more than it was found in clothing made from other fibers. One study labeled quinoline a potential human carcinogen, and reiterated the correlation of quinoline with polyester.

Last, heavy metals are a concern as well. They can be used in clothing in dyes, mordants, flame retardants, antimicrobials, water repellants, or in the manufacturing of synthetic fabrics. A 2015 study, "Human Exposure to Trace Elements Through the Skin by Direct Contact With Clothing: Risk Assessment" found high levels of chromium in polyamide dark clothes, high levels of antimony in polyester clothes, and high levels of copper in some green cotton fabrics. Overall, it found that all of the metals were well below the levels considered unsafe. However, this study had a very small sample size so its findings may not be conclusive.

A second study, this one only of underwear, also labeled heavy metals as a potential hazard in clothing. This study found that the presence of metals differed based on the fiber and the color of the dye. Cotton had more aluminum, iron and zinc; nylon had chromium, copper and aluminum; and polyester had higher nickel and iron. The highest levels of metals were in clothes manufactured in China, Egypt and India.

If your clothing has a design on it, it may contain another potential hazardous chemical. One type of ink used in screen printing, plastisol, may contain phthalates, which harm the reproductive system. A 2012 Greenpeace study found phthalates in all of 31 garments that had plastisol prints, with very high concentrations of phthalates in four of them. According to Greenpeace, phthalates are not bound very tightly to the plastisol inks, and they can be released over time.

A difficulty for consumers is that the chemicals used in dyes and mordants are not obvious when you are shopping for clothes. While you can find out what fiber the clothing is made of from the label, you don't know what was used to dye it. A small number of naturally dyed clothes are available for sale online, and you could even dye your own clothes with natural dyes, but both of these options are difficult. In the former case, there's poor availability, limiting the styles and colors you can find; in the latter case, it's an awful lot of work. A better option may be improved regulation to ensure toxic dyes are not permitted in clothing in the first place, or at least disclosure on labels if quinoline or azo dyes were used.

Bells and Whistles: Extra Chemicals in High-Tech Clothes

Want your shirt to be wrinkle-free, stain-resistant, bug repellant, antibacterial, waterproof/breathable, and UV protective? Each of these attributes may mean more chemicals in your clothing. Fortunately, you can opt not to buy clothes with these attributes. And while manufacturers are not required to disclose these traits on the label, they generally do because these traits are seen as desirable to consumers. Companies expect you will choose to buy their products because they are wrinkle-free and stain-resistant, not choose to avoid them.

To start, wrinkle-free clothing may be treated with formaldehyde. Formaldehyde is a carcinogen, but it can also be an allergen for some people.  

Clothing that promises sun protection may not have any extra chemicals in it. The type of fiber and the fabric thickness and the fabric weave can all provide sun protection. However, benzothiazoles and benzotriazoles are potentially toxic chemicals that are used to add sun protection to clothing.

Bug repellent clothing is impregnated with permethrin, a pesticide. One study found that your body absorbs 2 percent of the permethrin in your clothing, and another 1.2 percent of the permethrin remains on your skin's surface. That does not sound like much, but the question is whether that amount of permethrin can cause harm or not. Since you are presumably wearing this clothing due to a bug problem, you have your choice of risking bug bites, using repellents like DEET, wearing clothing with permethrin, or employing any other option you can contrive to avoid the bugs, like covering up with normal, non-bug repellant clothing. (I'll often opt for the itch to avoid using chemicals, but I wore an entire permethrin-treated outfit from head to toe when foraging for mushrooms in an area with a lot of Lyme disease and when visiting a malarial region in Kenya.)

Antibacterial clothing can also have chemicals in it. Some fibers are antibacterial—hemp and linen in particular, but also merino wool—but often clothing marketed as antibacterial or antimicrobial uses something else, like nanosilver.

Waterproof/breathable and stain resistant clothing generally use perfluorinated chemicals (PFCs). Teflon and GorTex are PFCs. They are slippery and used for non-stick and stain-resistant products. Unfortunately, PFCs are not very good for human health.

Flame retardants are another group of chemicals that can be highly toxic. In recent decades, several popular chemicals were used and then phased out, only to be replaced by others. For many years, PBDEs (polybrominated diphenyl ethers) were a common flame retardant. However, they were phased out internationally over a decade ago under the Stockholm Convention on Persistent Organic Pollutants. A chemical known as chlorinated tris or TDCPP was one of the flame retardants used after that, but it was phased out, as it is carcinogenic.

Today, flame retardants tend to be either chlorinated or brominated organohalogens or organophosphates, many of which are toxic. There is very little transparency about which flame retardants are used in clothing. Often the only clue you have that your clothing has been treated with a flame retardant—and you have no way of discovering which one—is a tag saying something about how the garment complies with a flame retardant regulation, but is still flammable.

In all of the above cases, you generally can tell if clothing is likely treated with a chemical of some sort because it boasts stain resistance or antibacterial properties, etc. You can choose to buy clothing that does not have these properties. What you generally can't do is find out which chemicals were used in the clothing, as that is typically proprietary.

In summary, seeking out non-toxic clothing can be complicated—and that's without even considering the environmental impact of the clothes. You can opt for natural fibers, and even choose organic cotton to be sure no pesticides were used, and you can avoid clothes that promise special traits like wrinkle-free and so on. Even still, you won't know what was used to dye your clothing, or if it's harmful. In theory, we have government regulation to alleviate this concern by banning anything that can harm us. Unfortunately, that's not the reality we live in.