Hoka One One · Waterproof Boots
Hoka One One Hoka U Kaha 3 GTX TP
GTX and water-repellent coating finishes typical use PFAS; brand silent on chemistry.
Hoka does not disclose PFAS use in this hiking boot. Gore-Tex and water-repellent coating coatings commonly contain PFAS, but no lab data or brand statement confirms presence here.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Textile upper with GTX waterproof membrane, unspecified water-repellent coating treatment
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What Hoka One One Hoka U Kaha 3 GTX TP is made of, ingredients and materials
This hiking boot pairs a textile upper with Gore-Tex (GTX) waterproof membrane and an unspecified water-repellent coating (water-repellent coating) topcoat. Gore-Tex itself is a Teflon-type coating film that does not shed or leach under normal wear; the hazard lies in the water-repellent coating finish applied to the outer textile, which is almost certainly PFAS-based unless explicitly stated otherwise. Textile uppers are typically polyester, nylon, or cotton blends; the specific fiber composition of this model is not publicly detailed.
What’s concerning
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
PFAS
Unspecified water-repellent coating treatment on textile uppers; industry default is PFAS-based fluorocarbon. Hoka silent on alternative chemistry. PFAS does not typically leach into skin under normal wear but accumulates in the environment and body with repeated exposure to multiple PFAS-treated products.
Source, ATSDR ↗Formaldehyde / VOCs
Textile dyeing and finishing can involve formaldehyde-releasing resins for water resistance, shrinkage control, or dye fixation. Hoka does not publish finish specifications. Risk is lower than for industrial apparel but not ruled out by available information.
Source, ATSDR ↗Azo dyes in synthetic fibers
Polyester or nylon uppers may be dyed with azo dyes, some of which are restricted under EU regulations but not universally banned. Hoka does not disclose dye chemistry. Skin contact risk is low; concern is more environmental and occupational during manufacturing.
Antimony in polyester
If the textile upper is polyester, antimony trioxide may be present as a polymerization catalyst. Levels in finished textiles are typically trace and not reported to migrate under normal wear. Hoka does not disclose fiber sourcing or antimony testing.
Coating degradation and microparticle shedding
GTX membrane and water-repellent coating coatings degrade with age and washing. Shed microparticles (Teflon-type coating, Teflon-family coating, dyes) can enter soil and water during care or disposal. Frequency and scale are not quantified for this specific model but are a known feature of coated hiking boots.
The full breakdown
The brand's record and disclosure
Hoka One One has not published a transparency statement, restricted substance list, or PFAS phase-out commitment on the public record. The brand does not disclose water-repellent coating chemistry or waterproofing standards for its products. No major product recalls or formaldehyde/heavy metal scandals are documented for Hoka footwear, but the absence of disclosure makes independent verification of chemical safety difficult.
How it compares in its category
Most mainstream hiking boots at this performance tier (GTX + water-repellent coating) use similar PFAS-based water repellents; Hoka's approach is industry-standard, not distinct. Brands like Salomon, Merrell, and La Sportiva employ the same chemistry without public phase-out. Smaller brands (e.g. Danner, some European makers) have begun adopting PFAS-free water-repellent coating alternatives, but these remain niche. This boot is typical for its category, not an outlier in hazard profile.
If you buy it
Avoid machine washing; hand wash with mild soap and rinse thoroughly to minimize water-repellent coating reapplication frequency. Do not tumble dry or expose to heat above 60°C, as heat may accelerate polymer degradation and potential leaching. Plan for water-repellent coating reapplication every 1-2 seasons of heavy use; use PFAS-free aftermarket products (e.g. wax-based) if available to limit cumulative exposure. Replace boots when structural integrity (sole, seams) fails, not on an arbitrary schedule.
What we don’t know
- Basis
- Model estimate, 35% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Hoka One One has made none
Formulations change between production runs, so check the current label. How we grade.
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Find an alternative on AmazonMore waterproof boots 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.