Coros · Waterproof Fitness Trackers
COROS Pace 4 GPS Watch
Waterproof smartwatch; PFAS risk from unspecified water-repellent coating unclear.
COROS makes no public PFAS disclosures for the Pace 4. Waterproof electronics typically use water-repellent coating coatings, which may contain PFAS, but specifics are not disclosed.
The safe swap
Withings
Withings BeamO 3-in-1 Health MultiScan
100/100 safety
Same rubric that flunked this product. The swap earned its A.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Plastic case, glass screen, waterproof coating (unspecified)
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Waterproof / stain-resistant treatment
water-repellent coating treatments have historically used PFAS.
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The COROS Pace 4 uses a plastic composite case (likely reinforced polymer), mineral or hardened glass screen, and an unspecified waterproof/water-repellent coating. The plastic casing avoids heavy metals common in metal watches but introduces potential off-gassing of volatile organic compounds (VOCs) during manufacturing and storage. The waterproof treatment is the primary chemical concern, as manufacturers typically use fluorinated compounds (including PFAS) to achieve water resistance on textiles and electronics, though COROS has not disclosed their specific formulation.
The brand's record and disclosure
COROS is a sports watch manufacturer with no published independent safety certifications, hazard disclosures, or formal PFAS avoidance statements available in public records. The brand has not faced recalls related to chemical hazards on this model. Transparency around material composition and waterproof coating chemistry is absent, making independent verification of safety claims impossible. No third-party testing results for heavy metals, VOCs, or PFAS are on record for COROS products.
How it compares in its category
Most GPS sports watches (Garmin, Apple Watch, Fitbit) use similar plastic and coating architectures and face identical PFAS/waterproofing trade-offs without formal disclosure. COROS occupies the mid-tier market with equivalent or slightly lower transparency than competitors. Watches designed for extreme sports or diving tend to rely more heavily on fluorinated coatings to achieve depth ratings, but the Pace 4 is a standard running watch with modest waterproof specs (10 ATM / 100m), suggesting less aggressive chemical treatment may be possible.
If you buy it
Rinse the watch regularly under fresh water after saltwater or chlorine exposure to minimize coating degradation and chemical leaching. Avoid prolonged direct heat (>60C) which can accelerate VOC off-gassing and coating breakdown. Replace the watch if the waterproof seal visibly degrades or if water enters the casing, as this signals potential plastic micro-damage. Store in a cool, dry place away from direct sunlight to slow off-gassing.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Waterproof coating chemistry (likely PFAS)
Unspecified fluorinated or hydrophobic coating is standard for waterproof electronics; COROS has not disclosed whether PFAS-free alternatives are used. Skin contact risk is low due to limited surface area and short contact time, but coating microflakes or vapor release during manufacturing/early life is not quantified.
VOC off-gassing from plastic case
Reinforced polymer cases can emit formaldehyde, benzene, or toluene during initial use or under heat stress. No measurements available for this model; typical consumer electronics off-gassing is considered low-level but unquantified for sports watches.
Coating degradation and microplastic release
Water-repellent coatings can crack or peel over time, particularly after saltwater/chlorine exposure or mechanical stress. Microscopic coating fragments may enter water or contact skin; no testing on COROS Pace 4 specific degradation rates is available.
Glass screen integrity and heavy metals in pigments
Mineral or hardened glass screens are generally inert; no recalls or hazard reports exist for COROS displays. If glass is colored or bonded with adhesives, trace heavy metals (cadmium, lead) in pigments are theoretically possible but unconfirmed.
Battery and internal electronics leaching
Internal lithium battery and circuit boards follow generic electronics safety standards; no specific defects or leaching issues are documented for COROS Pace 4. Risk is minimal under normal use but increases if the device is damaged or submerged beyond rated depth.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 45% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Waterproof Fitness Trackers
Withings
BeamO 3-in-1 Health MultiScan
Medical-grade stainless steel, plastic housing, medical sensors
Medical device with inherently low PFAS risk profile.
✓Naturally PFAS-free material
Whoop
Peak Health and Fitness Wearable 12-Month Membership
silicone band, electronics, stainless steel hardware
Wearable membership with minimal PFAS risk indicators.
⚠Brand says nothing about PFAS
Whoop
MG Navigator Band
Elastomer band (silicone-based or similar)
Lower concern fitness band, but brand silence on materials limits certainty.
⚠Brand says nothing about PFAS
More waterproof fitness trackers grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.