Osprey · Waterproof Outdoor Gear Storage Bags
Osprey Sirrus 24 Backpack
High risk. water-repellent coating-treated outdoor pack with undisclosed PFAS status.
Osprey's daypack does not publicly disclose PFAS content or water-repellent coating chemistry. Typical outdoor backpacks use PFAS-based water repellency treatments without confirmed alternatives here.
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Material
Nylon/polyester with water-repellent coating finish
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.
water-repellent coating degradation and reapplication safety
Over 2-4 years of heavy use, water-repellent coating coatings wear and require reapplication. Consumer aftermarket water-repellent coating treatments vary in chemical composition and may contain undisclosed PFAS or other water-repellents; re-treating with unknown formulations introduces new chemical exposure not covered by original manufacturing.
Microplastic shedding from nylon/polyester
All synthetic fabric packs shed microplastics during washing and wear, particularly if the outer coating degrades. This is an environmental hazard rather than direct consumer toxicity, but relevant to lifecycle impact of the product.
What’s reassuring
Azo dyes in polyester/nylon
No evidence of restricted azo dyes in Osprey Sirrus 24 colorways on record. Osprey does not specify dye sourcing, but outdoor gear in this class rarely involves problematic azo chemistry.
Antimony in polyester
Antimony trioxide is used as a flame retardant and catalyst in some polyester manufacturing. Osprey does not disclose antimony levels; standard outdoor backpack polyester typically contains trace amounts with lower concern for skin contact under normal use.
Formaldehyde / VOCs
No formaldehyde-based wrinkle-resist or anti-microbial treatments are confirmed on this pack model. water-repellent coating finishes are the primary coating; fluorine-based water-repellent coating does not release formaldehyde.
Source, ATSDR ↗The full breakdown
What it's made of and why it matters
The Sirrus 24 uses nylon and polyester as base fabrics, both synthetic polymers that are inherently stable and do not leach chemicals under normal conditions. The critical component is the water-repellent coating (water-repellent coating) finish, a chemical coating applied to the exterior to shed water without compromising breathability. water-repellent coating finishes are typically either fluorine-based (PFAS, which Osprey has not disclosed) or fluorine-free alternatives; Osprey's specific chemistry remains proprietary and unavailable to consumers.
The brand's record and disclosure
Osprey has not publicly committed to PFAS-free water-repellent coating formulations or provided transparency on their chemical suppliers, unlike some competitors (e.g., Patagonia's move toward fluorine-free finishes). The brand does not list environmental or chemical certifications on the Sirrus 24 product page. No recalls or chemical safety incidents involving this model are on record, but the lack of disclosure contrasts with industry leaders who now publish supply-chain commitments.
How it compares in its category
Most mid-range outdoor packs (REI Co-op, Deuter, some Patagonia models) either disclose water-repellent coating type or offer fluorine-free alternatives. Osprey's silence on this issue is increasingly uncommon in the outdoor gear market, where PFAS awareness has driven competitor differentiation since 2019-2020. For a pack in this price tier and reputation, transparency is a notable gap relative to newer entrants focused on sustainable outdoor goods.
If you buy it
Nylon and polyester are not materials linked to PFAS; the pack's durability and water resistance will persist through several years of outdoor use without known degradation into microplastics under typical conditions. Avoid prolonged exposure to direct high heat (e.g., leaving it in a hot car or near flames), which could theoretically accelerate coating breakdown. Wash occasionally with cool water and mild soap; do not dry-clean, which may degrade water-repellent coating. Replace the pack if the outer fabric shows persistent peeling or flaking of the finish, which may indicate degradation of the coating layer.
What we don’t know
- Basis
- Model estimate, 35% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Osprey has made none
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Waterproof Outdoor Gear Storage Bags
REI Co-op
Trailgate Gear Bin Green 140 L
Polypropylene storage bin, no water-resistant coating mentioned
UV degradation and additive leaching
Limited concern
Microplastics
Limited concern
Odor and volatile organic compounds from manufacturing
Limited concern
Lower PFAS concern for bare plastic storage container.
⚠Starting grade for this product type
Marmot
Tool Box
Nylon, polyester, cotton blend; details unspecified
Volatile organic compounds (VOCs) from polyester and nylon manufacturing
Limited concern
water-repellent coating (water-repellent coating) coating chemistry unknown
Moderate concern
Formaldehyde / VOCs
Limited concern
Azo dyes in colored polyester components
Limited concern
Verify this is not a garment and check for any water-repellent coating applied.
⚠Starting grade for this product type
Patagonia
Guidewater Roll-Top Pack
nylon ripstop with water-repellent coating finish
PFAS
Limited concern
Nylon microplastic shedding (abrasion)
Limited concern
Degradation and leachate from aging water-repellent coating
Limited concern
A water-repellent or grease-resistant treatment of unstated chemistry, with a brand PFAS statement we have not verified.
⚠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.