According to a new study from the University of Notre Dame, your smartwatch band is exposing your wrist to so-called forever chemicals.Researchers found exceptionally high levels of perfluoroalkyl and polyfluoroalkyl substances (PFAS) such as perfluorohexanoic acid (PFHxA) in more expensive wristbands made from fluorinated synthetic rubber, a material manufacturers often use because its more durable than typical silicone. While the material, which resists discoloration and repels water, sweat, and oil, is great for a workout, those exceptionally high levels of PFAS, combined with long-term skin exposure, also present a potential health hazard to consumers, the study found.Researchers tested 22 smartwatch and fitness tracker wristbands from Apple, CASETiFY, Fitbit, Google, KingofKings, Modal, Nike, Samsung, Tighesen, and Vanjua, and found PFAS were widespread, especially in the priciest brands.higher price = more PFASThe study, published in Environmental Science & Technology Letters, found that every wristband it tested with a cost of $30 or more was made with fluoroelastomersand contained potentially hazardous levels of PFAs. Most wristbands priced $15 or higher likewise were made with flouroelastomers and contained high levels of PFAs. The only wristbands free of these chemicals were those priced at less than $15.This discovery stands out because of the very high concentrations of one type of forever chemical found in items that are in prolonged contact with our skin, Graham Peaslee, a professor emeritus in Notre Dames department of physics and astronomy and one of the studys authors, said in a statement, referring to PFAS. That means theres an increased risk such chemicals could seep through human skin.Peaslee tells Fast Company the study didnt single out results for individual wristbands because of its small sample size, but had sufficient information to publish its findings showing several common brands use this type of wristband and thus they could advise consumers on how to avoid them without picking on specific companies.unique risksPFAS can be found everywhere, from food packaging and fire extinguishing foam to personal care products, meaning most Americans have been exposed to the substances, according to the Centers for Disease Control and Prevention. There are adverse health effects associated with exposure to PFAS, such as reproductive and developmental effects, but the study notes exposure limits are still being studied.When it comes to the wristbands, researchers found they had a median concentration of PFAS that was about four times higher than that found in cosmetics. In a study published in 2023, researchers found PFAS in cosmetics had a median concentration of about 200 parts per billion, while the median concentration for the tested wristbands was about 800 parts per billion. One wristband sample was even higher, at more than 16,000 parts per billion.The researchers had never before seen PFA concentrations at this level for any wearable consumer product applied to the skin, Peaslee says. They recommend reading product descriptions and sticking with cheaper wristbands made from silicone instead of fluoroelastomers.