Mountainsmith · Waterproof Outdoor Gear Storage Bags
Mountainsmith Backpack Raincover
Raincover material and coating composition not publicly disclosed.
Mountainsmith doesn't disclose PFAS status or coating chemistry for this raincover. Standard water-repellent coating treatments often contain PFAS, and without transparency, higher concern applies.
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Material
Polyester with water-repellent coating water-repellent coating, unspecified
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Mountainsmith Backpack Raincover is made of, ingredients and materials
This raincover is polyester fabric with a water-repellent coating (water-repellent coating) coating, a finish that typically involves fluorinated compounds or, less commonly, silicone or wax-based alternatives. Mountainsmith does not publicly specify which water-repellent coating chemistry they use, leaving the exact chemical profile opaque. Polyester itself is stable under normal use, but the coating composition directly determines whether flame retardants, formaldehyde resins, or other treatment chemicals are present.
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.
Formaldehyde / VOCs
Polyester textiles often use formaldehyde-based resins for wrinkle resistance and shape retention. Mountainsmith does not specify whether their raincover uses these treatments; low-level emissions are possible but typically minimal in outdoor gear after initial use.
Source, ATSDR ↗water-repellent coating (water-repellent coating) coating chemicals
Water-repellent coating coatings historically rely on fluorinated compounds (related to but distinct from PFAS), or increasingly on silicone or wax alternatives. Without disclosure, the exact chemistry of this raincover's water-repellent coating is unknown; potential for skin or inhalation contact during extended use is low but not zero.
Heavy metals
If the raincover is colored, synthetic azo dyes or heavy metal pigments could be present. No public testing or recalls on Mountainsmith raingear exist; compliance with standard textile safety regulations is presumed but not verified.
Source, FDA ↗Coating degradation and particle shedding
As water-repellent coating coatings age and wear, fine particles or residues may shed into the environment or come into contact with skin. Proper care and timely replacement reduce this risk; the product manual does not specify a lifespan.
What’s reassuring
Antimony in polyester
Polyester fiber itself may contain trace antimony from manufacturing catalysts. No specific reports link Mountainsmith polyester to antimony contamination, and residual levels in finished fabric are typically negligible.
The full breakdown
The brand's record and disclosure
Mountainsmith does not publish material safety data sheets, chemical transparency reports, or third-party certifications (such as bluesign or GOTS) for this raincover. No public recalls or documented chemical controversies specific to Mountainsmith raingear have been reported, but the brand's silence on water-repellent coating formulation is typical of mid-range outdoor brands that do not prioritize chemical disclosure. No evidence of a corporate PFAS reduction commitment exists in publicly available sources.
How it compares in its category
Raincover products are a niche subcategory; most comparable items use similar polyester-plus-water-repellent coating construction without public chemical specification. Brands like Patagonia and Arc'teryx increasingly disclose water-repellent coating alternatives (such as polyurethane or wax blends) and limit PFAS use, setting a higher transparency standard that Mountainsmith does not match. Budget raingear typically offers no such disclosure, making Mountainsmith's opacity unremarkable but not reassuring.
If you buy it
Wash the raincover in cool water with mild detergent before first use to reduce any loose finish residues. Avoid high heat (machine dry on low or air dry only); excessive heat can degrade coatings and potentially release volatile compounds. Replace if the water-repellent coating visibly degrades (water no longer beads), as deteriorating finish can expose underlying polyester. Store in a dry, well-ventilated space to prevent mildew and off-gassing.
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
- Mountainsmith has made none
Formulations change between production runs, so check the current label. How we grade.
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More waterproof outdoor gear storage bags 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.