On Running · Running & Athletic Shoes
On Men's Running Cloudultra Pro
Running shoe with water-resistant coating; PFAS status unclear.
On Running does not publicly disclose PFAS use or absence in this shoe. water-repellent coating-treated textiles often contain PFAS, but brand transparency is absent. Request specifics from On directly.
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Material
Textile upper with water-repellent coating treatment, CloudTec sole
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Waterproof / stain-resistant treatment
water-repellent coating treatments have historically used PFAS.
Category baseline
clothing is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
water-repellent coating (water-repellent coating) coating chemistry
On does not confirm whether the water-repellent coating treatment on the Cloudultra Pro upper is PFAS-based or fluorine-free. Historical water-repellent coating formulations in running shoes relied on PFAS; some manufacturers have reformulated, but On's status is unknown. Migration into sweat and skin contact during wear cannot be ruled out.
Polyurethane foam off-gassing (CloudTec sole)
Polyurethane foams in shoe cushioning may release volatile compounds (VOCs) during initial wear and storage, particularly in warm conditions. This is common across the category and typically subsides after a few days of airing. No specific off-gassing complaints documented for On's CloudTec.
Microplastic shedding from sole and upper wear
Textile uppers and polyurethane soles degrade with use, releasing microfibers and microparticles into the environment. This is inherent to synthetic athletic footwear and affects all major brands equally. Particle release increases with age and heat exposure.
What’s reassuring
Synthetic dye and finishing resin residues
No specific safety incidents reported for On Running footwear dyes or resins. Textile uppers typically undergo azo dye and resin cross-linking during manufacturing; regulated brands test for compliance with textile safety standards (OEKO-TEX, etc.), but On does not publicly certify this shoe to those standards.
Formaldehyde / VOCs
Textile manufacturers use formaldehyde-releasing resins for crease resistance and durability; On does not disclose whether its uppers are treated with such resins or screened for formaldehyde residues. No complaints or recalls specific to this shoe are on record.
Source: ATSDR ↗The full breakdown
What it's made of and why it matters
The Cloudultra Pro upper is textile (likely polyester or nylon blend) treated with a water-repellent coating (water-repellent coating) finish to shed moisture. The sole uses On's proprietary CloudTec foam (polyurethane-based cushioning). water-repellent coating treatments historically relied on PFAS fluorocarbons, though some brands have shifted to fluorine-free alternatives; On's specific chemistry is not publicly disclosed. The upper textile may also contain synthetic dyes and finishing resins applied during manufacturing.
The brand's record and disclosure
On Running has published sustainability commitments but does not publicly specify PFAS avoidance in footwear or confirm whether their water-repellent coating treatments are PFAS-free. The brand maintains general chemical management standards but lacks detailed material transparency typical of more disclosure-forward competitors like Allbirds or Patagonia. No major recalls or chemical safety controversies are publicly documented for this model. On's silence on PFAS specifically is notable given industry awareness of the issue since 2020.
How it compares in its category
Premium running shoes routinely use water-repellent coating-treated uppers; this is standard practice rather than unusual. Competitors like ASICS, Brooks, and Nike similarly treat textile shoes with water-repellent finishes, most without public PFAS disclosure. On's CloudTec foam is perceived as a design advantage but does not address chemical transparency. Shoes marketed as PFAS-free (rare in running) from brands like Allbirds or some Vivobarefoot models offer an alternative if PFAS avoidance is a priority.
If you buy it
Wash uppers gently in cool water to minimize any coating leaching; avoid heat treatment or machine drying. Replace the shoe when foam cushioning visibly compresses or loses support (typically 300-500 miles), as foam degradation can release microparticles. Do not soak or submerge for extended periods. If water-repellent coating repellency fades, resist re-treatment at home with commercial water-repellent coating sprays that may contain PFAS; contact On for approved refresh methods if offered.
What we don’t know
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- On Running has made none
Formulations change between production runs, so check the current label. How we grade.
Safer alternatives in Running & Athletic Shoes
New Balance
Women's Fresh Foam Arishi v4 Shoes
Mesh upper, Fresh Foam midsole, rubber outsole
Azo dyes and color-based toxins
Limited concern
Antimony in polyester
Limited concern
Standard athletic shoe with no known PFAS triggers, but no brand disclosure.
⚠Risky category by default
Diadora
Atomo V7000-2
Textile fabric, likely polyester or nylon blend
Azo dyes and synthetic dyes
Limited concern
Formaldehyde / VOCs
Limited concern
Antimony in polyester fibers
Limited concern
Adhesive and rubber off-gassing
Limited concern
No public PFAS disclosure; lower concern but unverified.
⚠Risky category by default
More running & athletic shoes 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.