$175 Onia Black Michelle One Piece Swimsuit Small Ymy1223 vs Women's Bottom Turn Racerback Bikini Top: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. $175 Onia Black Michelle One Piece Swimsuit Small Ymy1223 carries a failing PFAS grade, and we never recommend buying a failing product.
Onia
$175 Onia Black Michelle One Piece Swimsuit Small Ymy1223
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleAzo dyes and residual dye chemicals
PossibleElastane/spandex degradation and leaching
PossibleMicroplastic shedding
Our pick
Patagonia
Women's Bottom Turn Racerback Bikini Top
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleElastane (spandex) degradation under heat or chlorine
Where these two actually differ
- We flag Azo dyes and residual dye chemicals, Elastane/spandex degradation and leaching and Microplastic shedding on the Onia and not on the Patagonia.
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the Onia.
- The Onia is nylon/polyamide blend (standard swimwear fabric) where the Patagonia is Nylon/polyester blend with elastane (standard swimwear), which is most of the difference in these two grades.
- The gap is 25 points, wide enough that this is not a close call, and the Patagonia is the one to buy.
Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →
More swimwear: see the full ranking