Mountainsmith · Waterproof Outdoor Gear Storage Bags
Mountainsmith Epic Lumbar Pack
Typical outdoor pack; water-repellent coating likely contains PFAS, brand silent on specifics.
Mountainsmith doesn't disclose PFAS content or water-repellent coating treatment details. Most outdoor lumbar packs use fluorinated water-repellent coating coatings, though this brand hasn't confirmed or denied PFAS use.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Nylon with water-repellent coating water-repellent coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Mountainsmith Epic Lumbar Pack is made of, ingredients and materials
The Epic Lumbar Pack is constructed primarily from nylon fabric with a water-repellent coating (water-repellent coating) coating applied to the exterior. water-repellent coating coatings on outdoor gear historically use fluorochemical compounds to achieve water-shedding properties; the specific chemistry of Mountainsmith's coating is not publicly disclosed. Nylon itself is stable and low-toxicity in normal use, but the performance finish is the material of concern for this product class.
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.
water-repellent coating degradation and microparticle shedding
As the water-repellent finish wears over time, microscopic coating fragments may shed into the environment or contact skin. No specific data exists for Mountainsmith packs, but this is a documented concern for all fluorochemical-coated outdoor textiles with heavy use.
What’s reassuring
Formaldehyde / VOCs
Nylon packs sometimes receive formaldehyde-based resin treatments for wrinkle resistance or mildew prevention; Mountainsmith does not publish finishing chemistry, so presence cannot be ruled out but is not established for this model.
Source, ATSDR ↗Azo dyes in colored nylon
The Epic pack is available in multiple colors; azo dyes (which can release carcinogenic amines under certain conditions) are used in some nylon dyeing. No recalls or warnings exist for Mountainsmith packs, and modern textile suppliers typically avoid restricted azo dyes in developed markets.
Antimony in polyester thread or trim
If the pack uses polyester thread, webbing, or trim (common for durability), antimony trioxide catalyst residue is theoretically possible but not documented for this brand or product line.
The full breakdown
The brand's record and disclosure
Mountainsmith has not issued public statements regarding PFAS use, fluorochemical alternatives, or third-party testing of their packs. The brand does not advertise PFOA-free or PFAS-free manufacturing, nor do they appear on lists of outdoor gear makers committed to fluorochemical phase-out. This silence is typical of mid-tier outdoor brands but limits consumer ability to verify coating safety.
How it compares in its category
Lumbar packs in this price and feature range almost universally use fluorochemical water-repellent coating coatings; alternatives without fluorochemical water-repellent coating are rare and typically more expensive or less water-resistant. Mountainsmith's opacity matches industry norms rather than distinguishing them as worse, but it also means no competitive advantage in transparency. Consumers prioritizing PFAS avoidance will find few mainstream outdoor pack options without switching to niche brands.
If you buy it
Wash the pack in cool water with mild detergent; avoid machine washing or heat drying, which can degrade the water-repellent coating and potentially release coating particles. Reapply commercial water-repellent coating sprays if water repellency fades after 1-2 seasons of heavy use. Store in a cool, dry place away from direct sunlight to prevent nylon oxidation. Do not expose to high heat, open flame, or prolonged chlorine exposure.
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.