S'well Bento Box
Lower concern for rigid bento box; check lid seal material composition.
S'well's stainless steel bento is lower PFAS concern. Seals and gaskets are the unknown; contact S'well for their composition.
We flunk more products than we pass. This one earned its grade. How we grade
Material
stainless steel, plastic lid/seals
Lab data
No public lab test
What S'well Bento Box is made of, ingredients and materials
The S'well Bento Box uses 18/8 stainless steel for the main compartments, which is chemically inert and does not leach into food at normal storage or moderate heating temperatures. The lid and seals are plastic, the composition of which S'well has not publicly specified. Stainless steel avoids the BPA, phthalate, and leaching risks common to polycarbonate or polyvinyl chloride food containers, but the seal material and any adhesives joining components remain uncharacterized in published product information.
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Plastic lid/seal composition not disclosed
S'well does not publicly specify the polymer type or additives in the plastic lid and seals. If the material is polycarbonate or contains BPA/BPS, leaching into food is possible under warm conditions; if it is polypropylene or polyethylene, leaching risk is lower. Without transparency, verification requires direct inquiry.
Microplastics
If the plastic lid and seals are not engineered to food-contact grade, degradation from repeated washing, thermal stress, or contact with acidic foods could shed particles. The absence of published durability or material specifications makes assessment difficult.
Source, EPA ↗What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
BPA & bisphenols
No published test results or recalls name BPA, BPS, or phthalates in S'well Bento Box seals. However, because the brand has not disclosed seal polymer type or certifications, this hazard cannot be ruled out based on available information alone.
Source, FDA ↗Adhesives or coatings between steel and plastic components
No public information exists on adhesives or bonding agents used to join the stainless steel body to plastic components. If epoxy or other resins contain volatile compounds or leachables, risk exists but is not documented for this product.
Stainless steel body corrosion or nickel leaching
18/8 stainless steel (304 grade) is food-safe and resistant to corrosion under normal storage. Nickel leaching is negligible with this alloy in food contact. No public concerns are on record for S'well's steel bento boxes.
The full breakdown
The brand's record and disclosure
S'well is known for marketing on sustainability and design appeal, but does not publish material safety data sheets or third-party certifications (such as NSF or FDA compliance statements) for this product. The brand has not issued public statements on PFAS use in lids or seals, nor has it disclosed manufacturing standards for plastic components. No major recalls or contamination incidents are on record for this product line as of available public sources.
How it compares in its category
Food-storage bento boxes typically use plastic (polypropylene, tritan, or polycarbonate), glass, or stainless steel. The S'well design's steel body is a strength compared to all-plastic competitors, which carry BPA and phthalate leaching risk, especially under heat. However, the brand does not disclose whether plastic seals meet FDA food-contact standards or contain low-concern polymers like polypropylene, making direct comparison to transparent competitors (e.g., Rubbermaid Brilliance, Pyrex) difficult.
If you buy it
Inspect the plastic lid and seals regularly for cracks, cloudiness, or degradation; replace them if visible wear appears, since S'well does not publicly confirm replacement-part availability or composition. Avoid placing hot food directly against the plastic seal or heating the container in a microwave with the lid sealed. Hand wash the plastic components rather than top-rack dishwashing, as high heat and agitation can degrade polymers and increase leaching risk. Do not rely on S'well's marketing language alone; verify seal and lid material specifications with customer service before purchase if chemical composition is a priority for your household.
What we don’t know
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- S'well has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
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More lunch boxes grades
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.