Women's Bonded Swimsuit in Brown vs Women's Bottom Turn Racerback Bikini Top: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. COS Women's Bonded Swimsuit in Brown carries a failing PFAS grade, and we never recommend buying a failing product.
COS
Women's Bonded Swimsuit in Brown
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleAdhesive/bonding layer leachates
ReportedMicroplastic shedding from elastane
PossiblePFAS in water-repellent coating or water-resistance treatments
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 Adhesive/bonding layer leachates, Microplastic shedding from elastane and PFAS in DWR or water-resistance treatments on the COS and not on the Patagonia.
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the COS.
- The COS is Nylon/polyester blend with elastane (bonded swimwear construction) 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