Smartwatch bands linked to toxic PFAS risks

Thanks to the many benefits that smart watches provide, many now wear these devices on a daily basis. However, new research has come to light that questions whether they are safe to use, and how forever chemicals impact human health.

The Issue with Forever Chemicals

Anyone in the electronics industry who's taken a product from concept to commercial launch knows the minefield of RoHS and REACH compliance. Between restricting heavy metals, flame retardants, and halogenated compounds, the intent is clear: electronics should be safer to use, safer to dispose of, and far less toxic to the planet.

But even with these regulations in place, a quiet class of chemicals continues to fly under the radar: forever chemicals.

Forever chemicals, or per- and polyfluoroalkyl substances (PFAS), are named for their extreme environmental persistence. These compounds don't break down under typical environmental conditions, meaning once they're out there, they're really out there, potentially for centuries. Ironically, the same reason we use them (because they're chemically stable and non-reactive) is exactly what makes them a long-term hazard.

Take Teflon, for example. Used in everything from non-stick cookware to electronics manufacturing, it's celebrated for its resistance to heat, water, and just about every chemical you can throw at it. That same resistance means it sticks around, forever, and while that may sound benign, the emerging data says otherwise.

New studies are painting a troubling picture; even though these substances don't readily react, they can still accumulate in biological systems. This may be leading to potential links to infertility, hormonal disruption, and even certain cancers.

Right now, engineers aren't legally required to account for PFAS under most regulatory frameworks. RoHS and REACH are catching up, but they're not quite there yet. That means if a component uses a forever chemical in its encapsulation, insulation, or manufacturing process, it may still be fully compliant, even if it's environmentally questionable.

So, what should we do? This is where the industry needs to get ahead of the legislation. Just because a component passes current checks doesn't mean it's a sustainable or responsible choice. Engineers, especially those in design roles, need to start asking harder questions: What's in this material? Where does it end up? Could it affect the user over time?

As electronics continue to infiltrate every corner of life, from medical implants to children's toys, it's probably time we broaden our definition of "compliance" to include long-term chemical impact. Because "forever" is a long time to be wrong.

Your Smartwatch Might Be Leaking Forever Chemicals

If you thought forever chemicals were just something to worry about in industrial settings or contaminated groundwater, think again. They may be sitting on your wrist right now, quietly leaching into your skin. A recent study out of the University of Notre Dame found that many smartwatch wristbands contain high levels of PFHxA, a member of the infamous PFAS family of chemicals.

According to the study, PFHxA was found to leach from the bands in quantities that raised red flags for potential absorption through the skin. While PFHxA isn't yet one of the PFAS compounds strictly regulated in the U.S., it shares many of the health risks linked to its chemical cousins: hormonal disruption, liver toxicity, and even cancer.

Now, to be fair, the science isn't conclusive yet. The researchers themselves admit that dermal absorption rates are not fully understood, and that exposure levels depend on many factors, including wear time, skin condition, and material degradation. But even without definitive data, the mere presence of these chemicals in consumer-grade wearables should raise some eyebrows, especially when these devices are marketed as tools for health and wellness.

Latest Findings and Media Coverage

The Notre Dame research, published in late 2024, has continued to attract significant media attention through 2025. Outlets including Newsweek, The Guardian, and People reported that fluoroelastomer straps, used in popular brands like Apple, Nike, and Google, contained some of the highest PFHxA concentrations, in certain cases exceeding 1,000 parts per billion. Experts have noted that while definitive exposure pathways are still being studied, levels this high raise legitimate public health concerns.

Further analysis from ACS Axial suggested that dermal absorption under conditions like sweating could account for over 50% uptake, amplifying risks for users who wear their watches daily. While regulators debate how best to manage PFAS in consumer wearables, some scientists already recommend switching to alternative materials such as untreated silicone or fabric bands, which appear to carry far lower risks.

Should Engineers Start Examining Chemical Use?

The science behind forever chemicals isn't rock-solid yet, and there's still plenty we don't know about long-term exposure, bioaccumulation, or just how much of a problem compounds like PFHxA really pose, especially when absorbed through the skin.

But the fact is that while early data is rarely perfect, it's already pointing to real biological effects, including hormone disruption, cancer links, and organ damage. That alone should be enough to give engineers pause, especially those of us working on consumer devices meant to be worn against the skin every day.

Wearables aren't abstract machines sealed in enclosures; they're in direct, prolonged contact with real human bodies. That creates an added layer of responsibility, one that arguably goes beyond compliance checklists and government-mandated thresholds. Now, just because the regulations don't require action doesn't mean engineers shouldn't act.

Take smartwatch straps. Many are made from chemically treated polymers, sometimes including PFAS-based compounds that leach under normal wear. If even a fraction of the research holds up, that's a serious health concern in the making. This problem could be mitigated right now with alternative materials like untreated silicone or non-fluorinated elastomers. While it might cost more, we need to think about the long-term health costs.

But circuit design also deserves scrutiny, as many of the components we use (coatings, solders, conformal layers, fire retardants) rely on fluorinated compounds for durability and performance. But how many of us stop to ask what's in those layers? How many even can?

However, it's not just about end use, as there is also the supply chain to consider. The way parts are made, what chemicals are used during fabrication, and how waste is handled all feed into the environmental footprint of a product. Just because we don't see it on the spec sheet doesn't mean it isn't there.

The reality is, no product exists in isolation. Every choice, from a capacitor's resin to a wristband's polymer, echoes through the manufacturing process, the environment, and ultimately, the person using it.

Engineers have always been good at solving technical problems. But this might be one of those moments where we need to solve an ethical one, too.