Women's Bottom Turn Racerback Bikini Top vs Posidonia One Piece Swimsuit: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. Reformation Posidonia One Piece Swimsuit carries a failing PFAS grade, and we never recommend buying a failing product.
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
Reformation
Posidonia One Piece Swimsuit
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleAzo dyes and colorant heavy metals
PossibleFormaldehyde resins in finishes
PossibleAntimony in polyester
Where these two actually differ
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the Reformation.
- We flag Azo dyes and colorant heavy metals, Formaldehyde resins in finishes, Antimony in polyester and Skin irritation from dyes or finishes on the Reformation and not on the Patagonia.
- The Patagonia is Nylon/polyester blend with elastane (standard swimwear) where the Reformation is Nylon/polyester blend swimsuit fabric (standard synthetic), 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