Granite Gear · Waterproof Outdoor Gear Storage Bags
Granite Gear eVent Sil Compression DrySack
Waterproof coating source unclear; brand silent on PFAS.
This compression drysack relies on eVent laminate for waterproofing, a proprietary technology with undisclosed PFAS content. Granite Gear refuses to be transparent about PFAS anywhere in the product.
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Material
Nylon with eVent laminate and silicone coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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.
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
Nylon polymer degradation and microfiber release
Nylon fabric sheds microfibers under mechanical stress and abrasion, especially at seams and stress points. Washing, compression, or friction against rough surfaces accelerates this process, though the amount released during normal outdoor storage use is not quantified.
Silicone coating breakdown and leachables
Silicone coatings can degrade when exposed to prolonged UV, heat, or chemical solvents, potentially releasing siloxane compounds into contents. No specific testing of this product for silicone leaching has been published; risk is typical of silicone-coated textiles.
Laminate delamination and edge exposure
EVent laminates can peel away from the nylon substrate over time, particularly at seams, valve attachment points, and rolled edges. This exposes the adhesive layer and interior laminate materials, which may include residual processing chemicals not intended for direct contact with food or skin.
Mold and bacterial growth in damp interior
Any sealed, waterproof bag traps moisture and can harbor mold or bacteria if not fully dried after use. This is a maintenance issue, not a manufacturing defect, but requires regular inspection and air-drying to prevent contamination of stored items.
PFAS
EVent membranes and waterproof adhesives historically have used PFAS-based chemistry in similar products across the industry, though Granite Gear has not disclosed the specific formulation for this model. PFAS is graded separately; listed here to flag the structural hazard pathway.
Source, ATSDR ↗The full breakdown
What it's made of and why it matters
This bag uses nylon fabric laminated with an eVent membrane and coated with silicone. The silicone coating provides water repellency and durability without relying on Teflon-type coating (Teflon), which would off-gas harmful fumes if heated. However, the waterproofing mechanism, whether achieved through the eVent layer, silicone alone, or a combination, has not been transparently disclosed by Granite Gear, leaving uncertainty about whether PFAS chemicals are present in the laminate or coating.
The brand's record and disclosure
Granite Gear has not published detailed material safety data sheets or PFAS-use statements for this product line. The brand does not appear on major PFAS-transparency initiatives or certifications (such as OEKO-TEX or Bluesign). This silence on waterproof coating composition is typical among outdoor gear makers but limits your ability to verify PFAS absence. No established recalls or safety controversies specific to this model are on record.
How it compares in its category
Silicone-coated nylon drybags are a middle ground in the category. Some competitors use PU (polyurethane) coatings, which may or may not contain PFAS, depending on the supplier, while others rely on Teflon-type coating membranes (higher fume risk with heat). Granite Gear's eVent laminate approach is generally regarded as lower off-gassing risk than bare Teflon-type coating, but the waterproofing source remains ambiguous, which is a gap relative to brands that openly state PFAS-free coating chemistry.
If you buy it
Keep the bag away from direct heat sources, campfires, and high-temperature storage; nylon and silicone coatings degrade or release volatiles under sustained warmth above 60-70°C. Inspect the seams, laminate edges, and valve regularly for peeling or delamination, which signals coating breakdown and loss of waterproofing. Rinse and air-dry after saltwater or prolonged wet exposure to prevent silicone degradation and mold growth inside. Do not machine wash or tumble dry; hand wash only if needed, using cool water and mild soap.
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
- Granite Gear has made none
Formulations change between production runs, so check the current label. How we grade.
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⚠Waterproof or stain-proof treatment
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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.