New testing by a consumer advocacy group warns that a number of sports bras and athletic shirts on the market contain high levels of bisphenol A, or BPA, an industrial chemical that has been linked to cancer and other health concerns when exposed to the human body. The finding is prompting scientists and gear makers to more closely inspect next-to-skin materials.
“We feel like this is probably the tip of an iceberg and that there’s a lot more out there,” says Jimena Díaz Leiva, science director at the Center for Environmental Health (CEH), which conducted the testing and released the results in mid-October.
After six months of research, her team detected up to 22 times the safe limit of BPA, per California law, in polyester and spandex sports bras made by The North Face, Brooks, Nike, All in Motion, PINK, Asics, Athleta, and FILA. The group also found unhealthy levels of BPA in athletic shirts from The North Face, Brooks, Mizuno, Athleta, New Balance, and Reebok. The brands must respond to the violations by December 11 with their plans to remedy their materials. If they don’t, CEH plans to initiate litigation in California court.
Brooks Running says that BPA is already a banned substance in their products, and all materials are certified as safe by an independent third party. “We have no reason to believe any of our products do not meet any health/safety standards, but out of an abundance of caution, we are working urgently to investigate these claims,” a Brooks representative wrote in an email. The other brands have not responded to Outside’s requests for comment.
Concern over the possibility of BPA leaching out of apparel has even prompted brands not involved in CEH’s investigation to take stock of their material usage. The founder of Lume Six, Margaux Elliott, whose company makes sports bras with blended polyester fabric, contacted her suppliers as well as external testing facilities to confirm her material’s safety. Testing is costly, but she says she would rather ensure that her customers are safe.
“I’m trying to figure out where this is coming from so that I can make sure my product doesn’t have it,” Elliott says, adding that these findings should trigger industry-wide testing.
As some of the main fabrics used in outdoor gear and apparel, not to mention day-to-day clothing, polyester and spandex are virtually unavoidable. The “technical” materials are in everything from clothing to sleeping bags to tents. Petroleum-based polyester fibers are made by melting and extruding PET plastic pellets into long threads that are then spun into textiles. Spandex is derived from a synthetic polymer called polyurethane, which is also considered a plastic material.
According to Oeko-Tex, an association that certifies products are free from harmful chemicals, BPA enters the manufacturing process of polyester “as an intermediary step to improve the natural properties and lifespan of a fabric.” The chemical can be added to polyester and polyamide textiles to help dyes hold, prevent static, and boost flame retardance.
The CEH’s investigation into BPA in clothing began in fall 2021, when they discovered it in socks made predominantly with polyester and spandex, including styles from Saucony and Adidas. After socks, Díaz Leiva says, the researchers then turned to clothing, focusing on garments made for exercise, when high body temperature can activate leaching.
BPA can leach into food and drink from the containers that hold them, a discovery that led to legislative bans in baby bottles by the U.S. Food and Drug Administration in 2012. (By the way, your water bottle might be BPA-free, but manufacturers can just replace BPA with a whole host of alternative bisphenols that can cause the same kind of harm, scientists say.) However, the chemical can also end up in the bloodstream from absorption through the skin, such as when you sweat as you exercise.
It’s unclear if ingesting or absorbing BPA through the skin is worse for you, says Patricia Hunt, a molecular bioscience professor at Washington State University. About 25 years ago while studying mice, she was the first researcher to link abnormalities in egg chromosomes to BPA.
When ingested, BPA is immediately metabolized and most of it is released through urination, whereas when absorbed through the skin, the metabolic process slows and BPA hangs around longer in your body, she says. “You could argue that dermal delivery is a better way to get an exposure that’s going to have a biological effect.”
Immediate impact is difficult to measure, though. You may not get sick directly from BPA or other chemicals in plastics, but decades of research links even low levels of bisphenols to serious health issues like infertility, obesity, diabetes, and asthma.
The CEH place the onus on businesses, not individuals, to claim responsibility for the health impacts of plastic use. CEH sees litigation as the conduit for change: They want corporations to reformulate their products entirely with safer materials because they believe warning labels aren’t enough.
Because of the ongoing cases, Díaz Leiva could not share more about the CEH’s testing methods, such as how they chose the products and where exactly they found BPA. She could say, however, that they did not find BPA in natural materials like cotton and wool. That said, any natural fiber can be spun with plastic or coated with a chemical additive.
Check the tags of your gear, wear your polyester and spandex clothing less, and consider investing in wool or cotton garments instead.
The CEH recommends reducing exposure to polyester and spandex fabrics and avoiding the products on their lists. BPA doesn’t just wash out over time. “We have been telling people as much as possible to limit the amount of time that they wear their clothing,” says Díaz Leiva. “So after you finish a workout, take off your sports bra or your shirt.”