Polyester is in almost all of your clothing, and it’s almost impossible to recycle. Some innovators are looking beyond turning plastic bottles into fabric.

YOUR WARDROBE IS filled with plastic. Your sweat-wicking workout clothes, your running shoe uppers, your raincoat, your high-performance hiking gear, your office clothing. Check the labels. All of it probably has at least some polyester in it. Actually, that label is polyester, too.

Yes, in case you didn’t know (and the majority of people don’t, apparently?), polyester is a type of plastic made from fossil fuels. It’s the same plastic—polyethylene terephthalate, or PET—found in plastic water bottles that have the number 1 in the chasing arrow on the bottom. But while water bottles can be recycled, it’s almost impossible to recycle polyester. 

It’s true that plastics have made it possible to run faster, hike longer, and carry everything you need for an overnight mountaineering trip right on your back. Lightweight and high performance, polyester represents both the heights of human achievement and also, because it is so cheap and easy to make, our seemingly infinite capacity for destruction and waste. 

Traditionally, there were natural limits to how much clothing we could manufacture based on the land, water, people, and animals available to make materials like cotton, linen, leather, and silk.

There are scarcely any limits, however, to making virgin polyester from petroleum. Crude oil is refined into petrochemical ingredients like terephthalic acid and ethylene glycol. Those monomers are transformed by a chemical company into PET plastic. That is then formed into little pellets and shipped to a polyester mill, where the pellets are melted back down to be formed into fiber. 

As a result of this push-button process, fiber production has exploded, doubling in the past 20 years, while the world’s population has grown by only 25 percent. Today, half of the fiber used in fashion is polyester, a material that didn’t exist 100 years ago.  

Synthetic fibers now account for 1.35 percent of global oil production, according to a 2021 report by Changing Markets Foundation. More visibly, our tons of waste polyester and blended fabrics end up as trash all over the world. Witness the Atacama Desert in Chile being taken over by an invasive species of Global North clothing “donations.”

Synthetic fibers also shed off our clothing when we wear them and wash them—you might have heard that we ingest up to a credit card’s worth of plastic every week, and much of that is polyester fibers. Researchers are still exploring how this might be affecting our health, but given the fact that the hormone-disrupting chemical BPA has been found in polyester socks and sports bras, it can’t be good. 

Large brands, ever mindful of all the bad press around polyester, have responded by going in hard on recycled polyester. Just one example of many: In honor of Earth Day this year, Adidas announced that 96 percent of the polyester it uses is recycled. For an athletic brand like Adidas, that’s a big achievement. But this announcement was more … measured. 

“While we are proud, this is a step, not a solution,” Viviane Gut, senior director of sustainability at Adidas, said in the press release.

Why so negative? Well, this recycled polyester is not exactly what you might imagine. “One of the problems I always have with this is that they don’t actually specify that this comes from textiles,” says Ashley Holding, a sustainable textile consultant and founder of Circuvate. 

While water bottles can be recycled back into bottles several more times, once PET is made into polyester, that’s the last time it can be recycled.

He was not talking about Adidas specifically. Almost all brands rely on PET plastic water bottles to feed the recycling plants. And Adidas is very aware of the criticismthat recycling bottles into polyester is just another form of greenwashing, allowing brands to make feel-good claims about all the bottles that were saved from the landfill, which is, quite frankly, a stretch. If that were true, the proliferation of recycled polyester across these huge brands should have had some effect on the plastics recycling rate. Instead, at least in the US, the rate of plastics recycling is declining. 

Neither is polyester made from recycled bottles actually (cue the trumpets) circular, with clothing being made into new clothing forever. It’s more like the plastic made one quick loop back through the consumer world before heading to the landfill. The truth is, while water bottles can be recycled back into bottles several more times, once PET is made into polyester, that’s the last time it can be recycled.

Oh, and the microfiber problem is still there for recycled polyester. In fact, a recent study found that mechanical recycling plants can create massive amounts of microplastics that are flushed with the wastewater.

“From a circularity perspective, ideally we would recycle water bottles into water bottles and textiles into textiles,” Sharon Chen, director of business development at Baichuan Resources Recycling in China, told the Manufactured podcast in May. “The answer is: technology. It’s hard to maintain the purity needed to make a new bottle feedstock.” 

To mechanically recycle PET plastic—to melt it down and reform it—the material has to be pure and free of dyes, finishes, trims, or other types of plastics, like spandex. Clear plastic water bottles are so coveted because for the purposes of a textile mill, they’re essentially just dye-free, container-shaped pellets.

Used textiles, on the other hand, have all sorts of contaminants and come in vastly varying quality and colors. In Europe, used polycotton and other textile blends are collected at three times the rate of 100-percent polyester, and that doesn’t even account for the dyes and finishes present in pretty much everything. 

Imagine filling a blender with five flavors of ice cream, including some containing nuts and marshmallows and rainbow sprinkles. The blended result would be a disgusting gray mess. Oh, and some idiot dumped their spoon into the mix as well, so now your blender is broken. That’s about the state of used clothing collections.

The North Carolina company Unifi is one of the few manufacturers to sell a polyester made from recycled textiles. (It also creates a popular bottle-to-polyester recycled textile called Repreve.) Unifi has solved this contamination problem by only accepting pre-consumer, 100-percent-polyester waste straight from factories and mixing carbon black into the polyester while it’s gooey. The result is a pure black recycled polyester. Unlike polyester made from bottles, you could call it “circular” with a straight face.

Eddie Ingle, Unifi’s CEO, is tentatively interested in sourcing post-consumer polyester waste but admits, “You run the risk of getting people just dumping stuff on you.” He tells the story of receiving a pallet of bags the company was told were 100-percent polyester. His employees had to hand-cut out the non-polyester plastic bottom—an expensive proposition when you’re paying American wages. 

“We can sell black yarn all day long. We’re not worried about where we can sell the yarn. We’re worried about where to get supply,” he says. “Even though the actual textiles in theory would be cheaper because it’s waste textiles, that whole upfront collection, sorting, and prepping is what takes the money.” 

Polyester, polyester everywhere, and not a thread to recycle. 

Expensive Innovation for a Cheap Industry

Setting aside government action, the solution then would involve a recycling technology that can work with contaminated, blended polyester. In that sense, it’s a super exciting time for the fashion industry. “In the world of polyester, there’s quite a lot [of innovators],” says Kathleen Rademan, director of the innovation platform at Fashion for Good.

Brands like Asics, Helly Hansen, The North Face, Patagonia, and Brooks Brothers are already sending their old polyester stuff to Jeplan in Japan, which says its recycled polyester creates half the greenhouse gas emissions of virgin polyester that is incinerated at the end of its life. Ambercycle in Los Angeles received $21.6 million in a round of funding led by H&M in June 2022—you can buy some T-shirts made with its recycled polyester, Cycora, right now. The American chemical company Eastman is building a chemical polyester recycling plant in Tennessee that is slated to open this year.

All these innovators do what is called chemical recycling. Using slightly different technologies, they break PET down into its molecular ingredients, terephthalic acid and ethylene glycol, which are then fed back into the system to make fresh PET. To continue the ice cream metaphor, they’re breaking down all the different uneaten ice creams into sugars and proteins and getting rid of the colors and flavorings in the process. 

Antiplastic advocates have fiercely criticized chemical recycling as a fancy incineration process that is too high-energy, wasteful, and toxic to surrounding communities to qualify as sustainable. “There is no way to safely, economically recycle polyester textiles. Those ‘innovations’ are hoaxes and intentionally distractions,” Jan Dell, an independent chemical engineer and founder of the advocacy organization The Last Beach Cleanup, wrote to me via email. 

But that criticism is directed at pyrolysis, which uses a high-heat process to liquify plastics into fuel. These companies tend to distance themselves from pyrolysis by calling what they do molecular recycling. “The term ‘chemical recycling’ often implies high temperature processes that have an environmental impact and result in lower quality output, or downcycling,” says Ambercycle CEO and cofounder Shay Sethi in an email.

The Dutch startup CuRe, for example, has a pilot plant to test its polyester recycling technology, which outputs PET. While it hasn’t completed its assessment of polyester-to-polyester recycling, its peer-reviewed lifecycle analysis of its PET packaging-to-packaging recycling process shows an 88 percent carbon footprint reduction compared to virgin PET. Eastman’s publicly available LCA, on the other hand, claims a 29 percent reduction in emissions. 

Both Protein Evolution in Connecticut and Carbios in France focus on using an enzymatic process to break PET down into a monomer, but Carbios already has its technology available for license, and its commercial facility is slated to open in 2025. According to a 2020 paper in Nature cowritten by Carbios’ scientists and faculty from the Toulouse Biotechnology Institute, it only loses 10 percent of the polyester mass in the process of creating the monomer terephthalate. The company calls it “upcycling” because it can produce food-grade packaging from mixed and contaminated polyester.

The North Carolina startup Circ has a technology to recycle polyester-cotton blends, which make up 12 percent of old textiles collected in Europe today. It has gathered “truckloads” of old Patagonia gear the brand collected through its Worn Wear program, stuff that was no longer wearable or repairable, “really nasty stuff,” as Circ president Peter Majeranowski describes it. In April, Zara released a capsule collection of flowy lyocell pants, shorts, and a blouse that are 50 percent recycled fiber, and polyester garments that are 43 percent recycled fiber, all from Circ’s pilot plant.

“We’re not using any funky catalysts—solvents or anything like that—that are polluting,” Majeranowski says. “Our LCAs show us very much on the plus side of things from a greenhouse gas impact. But then also, we’re zero discharge.” So, no toxic emissions from a smokestack, and no nasty, microfiber-filled wastewater. All the water is purified and recycled back through the plant. 

But the question of economics looms over even the greenest technologies. “All of those processes are non-scalable and definitely not economic,” Dell says. 

Rademan agrees, at least with the “not economic” part. “The process that they all go through is expensive,” she says. “If I produce one of these raw component chemicals that goes eventually to polyester, I then need to … sell that on to someone who’s willing to buy it at the price that I’m currently selling it. That price is probably too expensive.” She wants to see brands commit to buying polyester made from recycled polyester and pay more for it.

Phony Threads

Everyone I spoke to acknowledged that recycled-bottle polyester fraud is happening already. Unifi puts a chemical tracer in its Repreve fabric so a piece of clothing can be tested to prove that it does indeed contain recycled polyester, and not an identical virgin fabric. Unfortunately, for the startups outputting monomers, chemicals are commodities, identical in every way except for their backstory. A physical tracer is not possible for molecules. So what’s to stop a plastics factory from taking a brand’s money and then turning around and purchasing cheaper, virgin chemicals and pocketing the difference? 

The answer to that question is a bit hazy. One pair of startup founders went silent for a very uncomfortable minute when I asked about the traceability of their product. Carbios’ CEO, Emmanuel Ladent, wrote in an email: “This is obviously an important point, and we are looking into several options but cannot communicate on these at this stage.” Other startups talk about partnering with trustworthy suppliers and putting tracers in once the fiber is constructed. But in an industry where very few brands know their supply chain down to the chemical supplier, recycled polyester fraud is not just a risk—it’s a reality.

Some have proposed a mass balance or book-and-claim system, where a brand could claim a certain amount of recycled content based on what it’s purchased, even if the actual material in a product isn’t from recycled sources. This recycled-on-paper approach to recycling has not been a popular proposal with sustainability advocates like Dell, who call it a “hoax.” But Majeranowski says it might be the only way to make the system work, comparing it to how we track renewable energy production and usage. As we track and measure electrons, we will measure molecules.

So the problem with recycling polyester is not a lack of innovation, but the economics, salted with a bit of distrust.

Plant Power

Maybe we should be moving away from petroleum and plastic altogether. Brooklyn-based Kintra Fibers, founded by a materials research scientist and avid surfer, creates a bio-based polyester, raising $8 million in April from several brands, including H&M. While the material won’t be ready for fashion for a couple of years yet, the startup claims it provides a suite of advantages. It’s soft and stretchy and can be plugged right into existing polyester equipment for a quick and relatively affordable scale-up. It’s made from sugars sourced from corn, and the goal is for it to be compostable in commercial facilities and to help address the microfiber problem.

There’s only one issue with this grand plan to replace petroleum with bio-based sources—we might not have enough arable land to grow all that material. And in the medium-term there could be destructive consequences: Witness biofuel’s link to rainforest destruction. (Kintra is aware of this criticism and says it wants to focus on getting the technology right before it tries using agricultural waste.)

So, as always, after wandering the labyrinth of innovation, we find ourselves looping right back around to the inevitable conclusion: We need to make and buy less stuff.

Does anyone have an innovation for that?