There are an estimated 40,000 to 60,000 chemicals used commercially today worldwide, and the vast majority of them haven't been tested for human safety. Many that have been tested are linked to serious human health risks like cancer and reproductive harm. And yet, they continue to pollute our air, water, food, and consumer products.
Among these is 1,4-dioxane, a chemical solvent that's been linked to liver cancer in lab rodents and classified as a probable human carcinogen. It's a multipurpose petrochemical, issuing from the brownfields of defunct industrial sites, chemical plants, and factories that use it in solvents, paint strippers, and degreasers. It shows up as an unintentional contaminant in consumer personal care products, detergents, and cleaning products and then goes down the drain into sewer systems.
It is also an unavoidable byproduct from the production of polyethylene terephthalate, more commonly known as PET, one of the most ubiquitous materials in the world. PET is the clear, odorless, food-safe plastic bottle you drink water out of. It's also the basis of the world's most popular fabric, used in everything from yoga leggings to baby onesies and area rugs; more than half of all fabric manufactured worldwide today is polyester. "You can't make PET polyester without creating this toxic byproduct 1,4-dioxane," Mike Belliveau, co-founder of the advocacy organization Defend Our Health, told me. "It's uniquely tied to the chemistry of the polymer."
To be clear, there is no 1,4-dioxane in polyester products themselves. But like so-called "forever chemicals," 1,4-dioxane dissolves quickly and completely into water, making it almost impossible to remove once it gets into a river or reservoir.
In 2012, the U.S. Environmental Protection Agency included 1,4-dioxane in the third iteration of what's called the Unregulated Contaminant Monitoring Rule, a list the agency puts out every five years of chemicals it considers suspicious and wants states to start testing for. The EPA's Toxic Release Inventory data shows that in 2019, the top four industrial producers of 1,4-dioxane in the U.S. were PET plastic or polyester factories; in 2022, it was five out of the top 10. That same year, a polyester manufacturer lost its permit to dispose of its waste at a treatment plant in New Jersey after state authorities discovered 1,4-dioxane in the drinking water and traced it back to the company.
Now, nearly 12 years later, not only has 1,4-dioxane proved to be shockingly prevalent, it has also been shown to be shockingly dangerous. The EPA may be on the verge of declaring, effectively, that almost any exposure to 1,4-dioxane constitutes an unreasonable risk to human health. Doing so would rock the American chemical and plastics manufacturing industry. But the alternative is being okay with rising cancer rates – an inconvenient fact the chemical industry would rather you not think about when you're at the store.
In the Water
North Carolina offers one representative case study. In 2013, a team from NC State University began testing for and finding 1,4-dioxane throughout the Cape Fear watershed, a network of rivers that starts in the mountains above Greensboro and flows southeast through Fayetteville and Wilmington before emptying into the ocean. At first, it was unclear exactly who the culprit of this widespread carcinogenic contamination could be. But by 2015, researchers had pinpointed a handful of sources: the wastewater treatment plants of Asheboro, Greensboro, and Reidsville.
Greensboro processed wastewater from an industrial waste transporter and chemical plant, Asheboro from a plastics plant, and Reidsville from Dystar, a dye and chemical manufacturer, and Unifi, a polyester manufacturer. DAK (now known as Alpek), another plastic manufacturer in Fayetteville, was also releasing 1,4-dioxane into the Lower Cape Fear River near Wilmington at a high enough level to consistently violate its permit. It is impossible at the moment to distinguish 1,4-dioxane's impact on the health of people in the Cape Fear watershed from the impact of the more infamous class of carcinogenic forever chemicals that also lurk there: PFAS. But as with many pollutants, in the U.S., 1,4-dioxane's is disproportionately found in Black and Brown communities.
Wherever PET or polyester is made, from the Gulf Coast to the Nakdonggang watershed in Korea, 1,4-dioxane is a problem. Typical water treatment technology can't remove it, so when polyester manufacturers or other industries discharge contaminated wastewater to municipal treatment plants, the carcinogen flows right through and ends up in the groundwater or watershed.
In North Carolina, the state, the cities, and manufacturers began arguing about what could, and should, be done about it. "My biggest concern in drinking water in North Carolina right now, it's 1-4 dioxane," Tom Reeder, Assistant Secretary for the Environment at the state Department of Environmental Quality, said in 2016.
Dystar and Unifi submitted remediation plans to Reidsville, and Dystar told the NC Department of Environmental Quality's Division of Water Resources that it was distilling the 1,4-dioxane out of its wastewater and storing it on-site. Dystar didn't answer Heatmap's questions, and Unifi said the spokesperson qualified to speak on the topic wasn't available. The NC DEQ referred Heatmap to Reidsville, which didn't respond to calls and emails. The lead 1,4-dioxane researcher at NC State also did not respond to requests for information or an interview.
Perhaps this is because of how contentious this issue has been for all involved parties. In 2022, the NC Environmental Management Commission attempted to make a rule limiting 1,4-dioxane in factory wastewater to .35 parts per billion. Unifi and Dystar wrote letters protesting the rule and Asheboro filed a lawsuit against the limits, with Reidsville attempting to join. The rule was eventually nullified because it didn't fully consider the financial burden it would impose on these cities.
But the way the science is going, these decisions may be taken out of North Carolina's hands.
An Unreasonable Risk
In 2016, Congress passed an amendment to the Toxic Substances Control Act (TSCA, or "toss kuh") instructing the EPA to fast-track risk analyses of chemicals of concern. Under the new law, if the EPA finds that a chemical poses an "unreasonable risk" to human health, it is required to regulate it down to reasonable levels — regardless of the economic impact. One of the first 10 chemicals on the docket was 1,4-dioxane.
Then, of course, came 2017 and the arrival of the Trump administration, which interfered to weaken EPA's published toxicity findings to make them cheaper for industry to comply with. For example, the 1,4-dioxane analysis excluded the risk of exposure via drinking water, even though more than 7 million people in the U.S. have drinking water with detectable levels of 1,4-dioxane. Many of the findings were repeatedly challenged in court.
When the Biden administration reanalyzed 1,4-dioxane, the draft findings published in 2023 said that 1,4-dioxane poses an "unreasonable risk" to the health of PET and polyester plant workers and people with contaminated drinking water. "As high as 2.3 in 100 exposed workers would be at risk of cancer over a lifetime of exposure," Jon Kalmuss-Katz, a senior attorney with Earthjustice, which has submitted comments to the EPA, told me. "The EPA considers the range of unreasonable risk to be one in 10,000 to one in a million." That's a 100- to 10,000-fold difference.
Some advocates saw a death knell for any remaining environmental arguments for polyester. "The federal government basically concluded that polyester PET poses an unreasonable risk to human health," Belliveau told me.
The risk evaluation has already gone through a comment period and a peer-review process, and the EPA expects to finalize its evaluation this year. When asked for comment, an EPA representative said, "Actual conditions and releases are highly variable and subject to site-by-site process conditions. The draft supplement to the risk evaluation should not be interpreted to suggest all sites that manufacture PET or polyester present unreasonable risk."
Despite letters from the American Chemistry Council, the Cleaning Institute, the Plastics Industry Association, and the PET manufacturer Alpek (formerly DAK) attempting to poke holes in the science, the advocates I spoke to were confident the "unreasonable risk" determination will stay.
At that point, the EPA has several tools it can use. "EPA can regulate manufacturing, can ban the chemical, can ban uses of the chemical, can restrict releases of the chemical to the environment," says Kalmuss-Katz. "But the underlying mandate is always the same. EPA has to ensure that the chemical no longer presents an unreasonable risk."
According to Thomas Mohr, a hydrogeologist who wrote the book on the investigation and remediation of 1,4-dioxane, polyester plants could simply require employees to wear respirators, and there are commercially available technologies available to filter out the chemical from wastewater — things like vacuum stripping and incineration, collecting it on a resin, or blasting it with ultraviolet light. But these processes are specialized and come with added costs.
That latter consideration is important for an industry that is already struggling to compete with low-cost polyester from China and other developing countries. Of the 115 American polyester manufacturing companies in the 1970s, only 12 remain in business today, according to a history book by Unifi, the polyester manufacturer in Reidsville.
Unifi barely survived the great textile offshoring of the late 1990s and early 2000s, mostly by shrinking and laying off large swaths of its workforce, buying and setting up plants in China and South America, and specializing in premium recycled polyester in its North Carolina plant. At the beginning of February, Unifi announced it would cut costs to shore up its finances. Adding a high-price treatment unit might be too much for it to bear. (Unifi said its spokesperson on this topic was not available for comment.)
Belliveau of Defend Our Health said he would be happy to see PET and polyester go away. But that's a far-off vision for such a popular material. "EPA is not known for its radical vision, so I doubt they're going to call for the shut-down of PET polyester in the U.S.," he told me. "They might say that we need to adopt a drinking water standard or put better control in plants for workers."
"Often there is a multi-year phase-out period," Kalmuss-Katz said. "There is time to respond to innovate and to develop safer alternatives and to get those out into use." Some of those alternatives could be polyester recycling technologies. France-based Carbios and California-based Ambercycle, both startups working on textile-to-textile polyester recycling, say their processes don't produce 1,4-dioxane. A representative for Circ, a Virginia-based textile recycling startup, would only say that it, "is adhering to all local and federal regulations to ensure its process is in line with the highest regulatory standards for safe chemistry… this is something the team will be following closely as data becomes more available."
Polyester has become a core part of almost everyone's wardrobe, used for its high performance, versatility, and affordability. More importantly for the Carolinas, it provides some of the few remaining jobs in a formerly vibrant textile center. To that, Kalmuss-Katz said, "Congress made pretty clear that the price of producing polyester cannot be fenceline communities are left with disproportionate and unreasonable cancer burdens."
Still, even if the EPA's decision is the final nail in the coffin of the PET and polyester industry in the U.S., it doesn't really solve the problem, or rather, not for everyone. Like other industries before it — leather tanning, rayon manufacturing, dye houses and dye manufacturing — it will continue to exist in its dirtiest form in other, less regulated countries. If the United States' past history of offshoring turns out to be prologue, most consumers probably won't notice the difference, except perhaps in slightly cheaper prices. Fashion companies will certainly notice, but are incentivized to look the other way.
For a few people paying attention, polyester will simply join a long list of products — chocolate, electronics, cheap meat — that come with a niggling feeling in the back of our minds: this has probably harmed someone on its way to me.
