Toxic PFAS chemicals are frequently used to make children’s clothing and textiles resist water and stains, but exposure to the compounds in clothes represents a serious health risk, a new peer-reviewed study finds.

The study, published in the Environmental and Science Technology journal, detected the chemicals in 65% of school uniforms, rain gear, snowsuits, snowshoes, mittens, bibs, hats and stroller covers tested, and at levels authors characterized as “high”.

“It’s one of those things where you hang your head and say ‘What are they thinking?’” said co-author and University of Notre Dame researcher Graham Peaslee. “Everyone thinks stain-resistant clothes are great progress, but if little Johnny or Jane is covered in PFAS, is that great progress?”

PFAS, or per- and polyfluoroalkyl substances, are a class of about 12,000 compounds used to make consumer products resist water, stains and heat. They are called “forever chemicals” because they do not naturally break down, and they accumulate in the environment and human body.