On Running Review, Is On Running Non-Toxic?
PFAS Authority is a scoring system, not a laboratory. We do not test products ourselves. Grades are model-based, built from published ingredients, materials, certifications, brand disclosures and third-party lab results where they exist. See the rubric.
Across 4 graded products, On Running averages Bad (20/100). On disclosure, the brand says nothing publicly about PFAS. None of its products grade Good or better yet. Grades are model-based estimates, not lab results.
Graded and flagged Poor and Bad, we’d swap these
On Running
Women's Waterproof Cloudrunner 2
textile with waterproof water-repellent coating
Antimony in polyester components
If the shoe contains polyester fiber (common in modern knit uppers), it may include…
Degradation of water-repellent coating releasing microparticles or additives
As the waterproof coating wears, it may shed fine particles into the environment or…
Waterproof running shoe, waterproofing often uses PFAS.
⚠Waterproof or stain-proof treatment
On Running
On Men's Cloud 6 Waterproof
Textile with waterproof coating
Waterproof coating degradation and leaching
On Running does not disclose the water-repellent coating treatment type; if…
Formaldehyde / VOCs
Synthetic textiles often undergo formaldehyde-based resin treatments for wrinkle…
Azo dyes in synthetic fabrics
Polyester and nylon uppers may use azo dyes, some of which are restricted in EU…
Antimony in polyester
Antimony trioxide is a common polyester catalyst; residual levels in On Cloud 6 uppers…
Waterproof treatment likely used; PFAS status undisclosed by brand.
⚠Waterproof or stain-proof treatment
On Running
Men's On Cloud 5
Knit textile upper with foam/rubber midsole; waterproof treatment likely applied
Formaldehyde / VOCs
Knit textiles may contain formaldehyde-based wrinkle-resist or antimicrobial finishes…
Azo dyes in knit upper
Synthetic knit textiles are commonly dyed with azo dyes, some of which are restricted…
Microplastic shedding from foam midsole degradation
EVA and polyurethane midsoles break down over time and shed microparticles, especially…
Glue and solvent residues in midsole-upper bonding
Polyurethane or polyester-based adhesives used to attach the upper to the midsole may…
Running shoe with likely water-repellent coating treatment; On Running does not disclose PFAS status.
⚠Waterproof or stain-proof treatment
On Running
On Men's Running Cloudultra Pro
Textile upper with water-repellent coating treatment, CloudTec sole
water-repellent coating (water-repellent coating) coating chemistry
On does not confirm whether the water-repellent coating treatment on the Cloudultra Pro…
Polyurethane foam off-gassing (CloudTec sole)
Polyurethane foams in shoe cushioning may release volatile compounds (VOCs) during…
Microplastic shedding from sole and upper wear
Textile uppers and polyurethane soles degrade with use, releasing microfibers and…
Running shoe with water-resistant coating; PFAS status unclear.
⚠Waterproof or stain-proof treatment
Every grade uses the same public rubric. How grades work →