PFAS score
REI Co-op · Waterproof Hiking Socks
REI Co-op COOLMAX EcoMade Lightweight Hiking Crew Socks (2 Pair
Lower-concern socks; synthetic fiber with no known waterproof/stain treatment, but PFAS use in polyester production not disclosed.
REI Co-op COOLMAX socks are made from polyester blends without advertised water-repellent or stain-resistant finishes, which lowers typical water-repellent coating-PFAS risk. However, REI makes no public commitment to PFAS-free manufacturing, and legacy polyester production sometimes involves fluorochemicals.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
COOLMAX polyester blend (synthetic fiber, no topical water-repellent coating treatment identified)
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Category baseline
clothing is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% 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.
More waterproof hiking socks 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.