Brooklyn, N.Y.—Journalist Alden Wicker examines a neon orange purse that’s selling for $14.99. She pulls a tag out of the bag: Instead of listing materials, it just says “vegan.” She raises an eyebrow. “Excuse me,” she asks a store clerk. “Can you look up the materials for this bag?”

Wicker and I have just stepped into an H&M pop-up in Williamsburg. The store clerk she’s waved over looks up the materials on his phone: The coating is polyurethane, and the lining is polyester. In other words: plastic.

For the last decade, Wicker has been covering the dirty side of fast fashion—from its contributions to the climate crisis to greenwashing to multilevel marketing schemes like the leggings brand LulaRoe. In 2013, she founded the blog EcoCult, and she soon became perhaps the most popular authority on sustainable fashion.

Her book, To Dye For, asks readers to consider the impact that chemically treated fabrics and synthetic fibers can have on your health. Wicker spent two years interviewing flight attendants, garment workers, physicians, researchers, industry experts, US consumers, and workers in the places where we source our clothes. She describes a supply chain rife with toxic chemicals—like formaldehyde and chromium, which are both carcinogenic—and endocrine-disrupting polyfluoroalkyl substances (also known as PFAS), which are linked to infertility and other health issues. And despite the potential harm, she discovered that the government has done little to protect consumers from the clothes they wear.

“We’re allowing chemicals to be poured indiscriminately into the environment, but we’re also bringing them into our homes,” Wicker tells me. The effects of these chemicals on textile workers and their communities were well-documented, but Wicker worries that the issue remained abstract to US consumers. “This isn’t an ‘over-there’ problem.”

Wicker got the idea for the book in 2019, when a radio producer called to ask if she could comment on a lawsuit filed by Delta employees against Land’s End alleging that the company’s uniforms were making them sick. “I’d heard nothing about fashion or textiles being toxic enough to affect people’s health,” she tells me. In fact, flight attendants at several major airlines were complaining of rashes, hair loss, fatigue, brain fog, heart palpitations, and breathing problems. “Their bodies would start shutting down,” she says. “They couldn’t work, and in some cases that completely ruined their lives.”

Early in the book we meet John, an Alaska Airlines flight attendant who developed a litany of health problems, including trouble breathing and blistering on his arms, right after he received a new uniform. Researchers at Harvard University attributed the attendants’ reactions to the long time they spent in them—flight attendants sometimes wear their uniforms for up to 24 hours at a time. A combination of chemicals, like anti-wrinkle and anti-stain resins and disperse dyes, can leach into the skin through sweat.

The flight attendants are just an extreme case of clothes making people sick, Wicker tells me. Over the course of her reporting, she dug up lawsuits against the children’s-clothing brand Carter’s and Victoria’s Secret, where people said their clothes gave them severe rashes. It’s difficult to prove the toxicity of a piece of clothing, she says, because a single shirt may have passed through several factories and can contain an untold number of chemicals.

“There’s no ingredient list in fashion,” Wicker says. “If you’re allergic to nickel or disperse dyes or formaldehyde, you can avoid it in beauty products, cleaning products, food products—but not in fashion.” In the book, she speaks with researchers who connect declining fertility rates and the rise of autoimmune diagnoses in the United States with chemicals found in our clothes.

We stop for coffee on Sixth Street, where Wicker tells me about the people she interviewed for To Dye For. She spent time with a textile worker in Tirupur, in southern India, whose arms and legs were covered in blisters that only started to disappear after she quit her job. She interviewed a California marketing executive whose dye allergies had caused her to scratch herself until she bled in her sleep. After eventually identifying the chemicals she was allergic to, she got rid of the clothes that were causing her reaction.