Cuppy · Insulated Travel Drinkware
Owala SmoothSip Slider Stainless Steel
Lower concern. Stainless steel and silicone lack typical PFAS carriers.
Owala SmoothSip uses stainless steel and silicone, materials not typically treated with PFAS. No brand PFAS disclosure found; no public lab testing reported.
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Material
Stainless steel body, silicone slider lid
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Stain-resistant finish
Stain-resistant finishes are a common PFAS use.
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The Owala SmoothSip Slider uses 18/8 stainless steel for the body, which is food-grade and highly resistant to corrosion and leaching under normal use. The slider lid is silicone, a synthetic rubber that does not off-gas volatile compounds at room temperature and tolerates cold/hot liquids without degrading. Stainless steel does not require polymer coatings (like Teflon-type coating or ceramic) that carry separate toxicity profiles, and silicone lacks the plasticizers (phthalates, BPA) found in many plastic closures.
The brand's record and disclosure
Cuppy has not published detailed material sourcing, manufacturing, or third-party safety certifications that are publicly available. The brand does not maintain a prominent safety or sustainability statement addressing PFAS, lead testing, or supply chain audits. No major recalls or health complaints tied to Owala products have been documented in U.S. regulatory databases. Absence of disclosure is not evidence of a problem, but limits independent verification of manufacturing controls.
How it compares in its category
Reusable stainless steel bottles with silicone lids are among the lowest-risk drink containers for chemical migration, outperforming plastic bottles (BPA/BPS, phthalates) and coated aluminum (potential for interior coating breakdown). Most competitors in this segment (Hydro Flask, S'well, Klean Kanteen) use similar stainless/silicone construction without documented leaching issues. The Owala's slider mechanism adds a moving part that may wear; durability and material integrity depend on routine cleaning and avoiding abrasive scourers.
If you buy it
Hand wash with warm soapy water after each use to prevent silicone odor absorption and mold growth in the seal. Inspect the silicone slider for cracks or degradation annually; replace it if visible wear appears, as a compromised seal may allow liquid to pool. Avoid dishwasher cycles above 140F if the lid is silicone-only, as prolonged heat can accelerate rubber aging. Do not use bleach or harsh solvents; mild soap and a bottle brush are sufficient.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Stainless steel leaching (nickel, chromium)
18/8 stainless steel is stable in neutral and acidic beverages at room and moderate temperatures. Leaching of nickel or chromium into water or juice is not established at normal use conditions, though prolonged contact with acidic drinks (pH <3) over years is theoretically possible.
Silicone degradation and off-gassing
Food-grade silicone used in closures does not release volatile organic compounds (VOCs) or monomers at room temperature or in contact with cold/warm drinks. No documented off-gassing events for Owala silicone sliders have been reported.
Microbial growth and biofilm in slider mechanism
The moving silicone slider creates a crevice where liquid can pool if not dried thoroughly after washing. Residual moisture in the groove may support mold or bacterial colonization if the bottle sits unused for days; regular cleaning and air-drying mitigate this risk.
Thermal degradation of silicone under extreme heat
Silicone sliders are safe for cold and warm beverages (up to ~160F for short periods). Boiling water or repeated dishwasher cycles above 140F may accelerate rubber hardening and loss of elasticity over years, but does not produce toxic byproducts at normal use temperatures.
Stainless steel manufacturing residues (oil, metal fines)
Food-grade stainless steel bottles may retain trace machining oils or metal dust from manufacturing if not properly passivated. A new bottle should be rinsed with hot water before first use; this is standard practice for stainless steel vessels.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 82% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
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How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.