Sea to Summit · Waterproof Smartphone Cases
Sea to Summit TPU Guide Waterproof Case
TPU waterproof case with undisclosed treatment. Moderate uncertainty.
Sea to Summit's TPU case uses waterproofing but the brand does not reveal PFAS content or water-repellent coating chemistry. Standard TPU is lower concern than Teflon-family coating coatings.
The safe swap
Mophie
Mophie Juice Pack Battery Case for iPhone 15
85/100 safety
Same rubric that flunked this product. The swap earned Excellent.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
TPU (thermoplastic polyurethane) with waterproof treatment
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Waterproof / stain-resistant treatment
Water-repellent treatments have historically contained PFAS chemicals.
Category baseline
PFAS exposure happens more often with clothing products.
No PFAS disclosure
The company has not publicly discussed PFAS in this product.
PFAS
Sea to Summit has not disclosed whether the waterproof treatment on this TPU case contains PFAS-based durable water repellents (DWRs) or alternative chemistries. Historical industry practice suggests legacy DWRs often contained PFOA/PFOS or related compounds; current alternatives vary widely.
Source: ATSDR ↗TPU thermal degradation and fume release
If heated above its glass-transition temperature (typically 60-80C depending on formulation), TPU can release volatile organic compounds. While not classified as acute hazard like Teflon-type coating cookware fumes, prolonged heating in enclosed spaces should be avoided.
Coating degradation and secondary exposure
Waterproof coatings on flexible materials can crack, peel, or flake with age and use. Degraded coating may shed microparticles or expose underlying treatment chemicals; regular inspection is recommended.
Fragmentation and microplastic shedding
Like all synthetic polymers, TPU can degrade over time with UV exposure and mechanical stress, generating microplastic particles. Extended outdoor use without protective storage may accelerate this process.
What’s reassuring
Plasticizer leaching into stored contents
TPU itself contains fewer problematic plasticizers than older PVC or vinyl alternatives. No established reports of leaching from TPU waterproof cases into food, water, or skin contact items under normal storage.
The full breakdown
What it's made of and why it matters
TPU (thermoplastic polyurethane) is a synthetic polymer that is inherently flexible, durable, and water-resistant without coating. Sea to Summit applies an additional waterproof treatment to this case, but the company has not publicly disclosed the chemical composition of that treatment. TPU itself does not leach BPA or phthalates under normal storage conditions, making it safer than many soft plastics. The undisclosed treatment is the primary concern, as waterproof coatings on textiles and plastics often historically used PFAS-based durable water repellents.
The brand's record and disclosure
Sea to Summit is an outdoor gear company with no publicly available PFAS policy or waterproof-treatment ingredient disclosures for their cases. The brand does not appear on major lists of companies with established PFAS phase-out commitments (such as ZDHC Gateway or manufacturer pledges). No product-specific recalls or chemical contamination reports for this case are on record. This silence on formulation is a red flag in a category where waterproofing chemicals are a known hazard vector.
How it compares in its category
Waterproof cases and drybags are typically made from PVC, nylon with polyurethane coating, or TPU. TPU is generally considered a lower-hazard substrate than rigid PVC (which can leach plasticizers). However, competitors like Ortlieb and some Decathlon drybags have begun disclosing PFAS-free or PFAS-reduced treatments; Sea to Summit has not matched this transparency. The lack of certification (e.g., Bluesign, GOTS, or PFOA/PFOS-free claims) puts it in the middle-uncertainty tier for this product type.
If you buy it
Store the case away from direct heat and sunlight, as TPU can soften above 60C (140F) and any coating may degrade if heated. Do not place it in high-temperature environments or near heaters. Hand-wash with cool water and mild soap if needed; avoid harsh solvents or bleach, which can degrade the waterproof layer. Inspect regularly for coating wear or cracking; if the waterproof layer begins to flake or peel, consider replacement to avoid exposure to the underlying treatment residue.
What we don’t know
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Sea to Summit has made none
Formulations change between production runs, so check the current label. How we grade.
Safer alternatives in Waterproof Smartphone Cases
Mophie
Juice Pack Battery Case for iPhone 15
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Lithium-ion battery thermal runaway risk
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Electromagnetic field exposure
Limited concern
Counterfeit or degraded battery cell defects
Limited concern
No known PFAS use; battery cases rarely require fluorinated coatings.
⚠Brand says nothing about PFAS
Mophie
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Microplastic shedding from wear
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Lower concern; battery cases lack typical PFAS-prone coatings.
⚠Brand says nothing about PFAS
Pelican
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Polycarbonate thermal degradation and leaching
Limited concern
Rubber grip degradation and allergens
Limited concern
Microplastic shedding from wear
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BPA & bisphenols
Limited concern
Lower concern; typical phone case with no suspected PFAS use.
⚠Brand says nothing about PFAS
More waterproof smartphone cases 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.