In 2022, the Center for Environmental Health, a nonprofit consumer advocacy group based in California, tested sports bras, leggings, athletic shirts and other activewear and found high levels of the chemical bisphenol A (BPA) in those sold by Athleta, PINK, The North Face, Nike and Patagonia, among other brands. (CNN reached out to the companies for comment; a spokesperson for Athleta said the company was committed to safety standards, adding, “We believe the CEH claims have no merit and stand by our products and practices.”) This came just one year after the CEH found high levels of BPA in socks from over 100 brands.

This information spread quickly through women’s groups and group chats. As I was in the middle of researching my book “To Dye For: How Toxic Fashion Is Making Us Sick – and How We Can Fight Back,” my friends asked me how concerned they should be. My answer? Very concerned.