Can PFAS and flame retardants in children's clothing transfer through sweat?

What's actually in it

Children's clothing can contain two types of chemical treatments: per- and polyfluoroalkyl substances (PFAS) for stain and water resistance, and organophosphate esters (OPEs) as flame retardants. Both are applied during manufacturing and remain in the fabric through multiple washes.

When kids play, run, and sweat, that moisture changes the chemistry at the fabric-skin boundary. Sweat is slightly acidic and salty, which can pull chemicals out of fabric more effectively than dry contact alone.

What the research says

A 2025 study in Sci Total Environ tested how much PFAS and OPEs transfer from children's textiles to skin in the presence of artificial sweat. The researchers simulated real wearing conditions and measured dermal transfer rates with and without sweat.

Sweat amplified the chemical transfer compared to dry conditions. The acidic, salty nature of sweat acted as a solvent, pulling more PFAS and OPEs out of the fabric and onto the skin surface. Children sweat more during active play, exactly when they're wearing these clothes the hardest.

The study also tested the combined toxicity of PFAS and OPEs together, since kids are exposed to both at the same time from the same garment. The mixture was more toxic to cells than either chemical family alone. This cocktail effect is something single-chemical safety testing completely misses.

Choose children's clothing that's OEKO-TEX or GOTS certified, which limits both PFAS and flame retardant content. Wash new children's clothes several times before first wear, and avoid water-resistant or stain-resistant finishes on everyday play clothes.