Three scientists at the University of Notre Dame in Indiana have analysed the commercially available silicone wristbands of the most popular smartwatches.
The findings are worrying, with high concentrations of perfluorinated and polyfluorinated alkyl substances (PFAS) detected in some of them.
These substances break down slowly in the body and can accumulate to considerable levels over time. The consequences are still being researched, but the US Centre for Disease Control and Prevention (CDC) warns of such effects as increased cholesterol levels, changes in liver enzymes, high blood pressure and pre-eclampsia during pregnancy, kidney and testicular cancer.
Lawsuit against Apple
Now Apple has been sued by two Apple Watch wearers, who claim in the lawsuit that Apple should know about the harmful effects of the fluoroelastomers the company uses in its Apple Watch bands and inform its customers about these.
A fluoroelastomer is used in three types of bands in particular, including Apple sports bands, sports bands for the Nike version of the Apple Watch and the Ocean Band for the Apple Watch Ultra and Ultra 2.
The lawsuit was filed in a court in Northern California on 21 January 2025 and is designed in such a way that other injured parties can join a class action lawsuit.
In the study, researchers analysed a total of 22 wristbands from Apple, Nike, Casetify, Fitbit, Google, Kingo Kings, Modal, Samsung, Tighesen and Vajua.
Each wristband examined was assigned an anonymised identifier such as M1, I1 or E1; the results do not reveal in which wristbands exactly the scientists found a worrying level of harmful PFAS. (The scientists anonymised the wristbands according to price, I stands for “inexpensive” (up to 15 USD), M for “middle range” up to 30 USD and E – “expensive” (from 30 USD).
In some, the researchers measured 0 per cent PFAS, and in others 90 per cent (Table S8 on page 14). The plaintiffs assume that Apple’s wristbands contain a high proportion of perfluorinated and polyfluorinated alkyl substances, as the researchers concluded that over 50 per cent PFAS were detected in two out of three higher-priced wristbands.
What Apple has to say
Apple has not yet publicly responded to the study and the lawsuit, but in a white paper from November 2022 Apple states that it will gradually ban PFAS from its production. However, this will take time, according to the paper:
“A complete phaseout of PFAS from Apple products and processes will take time. We need to compile a comprehensive catalog of PFAS use in electronics, identify and develop non-PFAS alternatives that can meet the performance needs for certain critical applications, and take into account the time needed for material qualification. Lastly we need to ensure that the non-PFAS alternatives do not result in regrettable substitutions — where alternatives are as harmful as, or even more harmful than, the PFAS being replaced.”
The company also responded directly to our sister site, Macwelt:
“Apple Watch bands are safe for users. In addition to our own testing, we also work with independent laboratories to conduct extensive testing and analysis of the materials used in our products, including Apple Watch bands.“
However, the Apple Watch is just one of the many great smartwatch options out there. See our full guide to the best smartwatches for alternatives which are available without PFAs.
This article originally appeared on our sister publication Macwelt and was translated and adapted from German.
