Agency for Toxic Substances and Disease Registry (ATSDR)
Synthetic Vitreous Fibers Toxicological Profile
ATSDR Toxicological Profile
Hydrated Silica vs Glass Fiber in Mattress Flame Barriers
Comparison of amorphous hydrated silica vs crystalline glass fiber (fiberglass) in mattress fire retardants.
Silica is Safer Choice
Direct answer summary
Hydrated silica ($SiO_2 \cdot nH_2O$) and glass fibers differ fundamentally in their physical chemistry and health risks. Hydrated silica is an amorphous, non-crystalline mineral bonded directly into cellulosic viscose-rayon fibers; it vitrifies upon heating without shedding. Glass fibers (fiberglass) consist of brittle continuous or chopped synthetic vitreous filaments that fracture under mechanical stress, releasing microscopic glass needles that cause severe skin, eye, and lung irritation.
Key points
Hydrated silica is amorphous and bonded into soft viscose; it does not shatter or shed.
Glass fibers are rigid crystalline filaments that fracture into respirable glass shards.
Hydrated silica safely passes CPSC 16 CFR Part 1633 without contaminating homes.
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Verified Law Label
Interactive Visual Tool
Law Label & Material Audit
Inspect the physical law label tag, decode the state Uniform Registry Number (URN), and review certified material percentages under CPSC 16 CFR Part 1633.
What the law tag tells you
Uniform Law Label & Material Deconstruction
Under FTC 16 CFR Part 303 and IABFLO uniform law label standards, bedding manufacturers must disclose exact net filling weights using standardized generic fiber terms. Marketing buzzwords are prohibited under federal penalty.
▲ Sewn Into Seam (Tyvek Substrate) ▲
UNDER PENALTY OF LAW THIS TAG NOT TO BE REMOVED EXCEPT BY THE CONSUMER
ALL NEW MATERIAL CONSISTING OF
POLYURETHANE FOAM PAD60%
GEL-INFUSED POLYURETHANE FOAM25%
RAYON FIBER FIRE BARRIER15%
Net Filling Weight (Excluding Steel Springs)
Uniform Registry Number (Click to decode)
REG. NO. NC-009876 (WI)
Certification is made by the manufacturer that the materials in this article are described in accordance with law.
Manufacture Date:02/2026
Plant Facility:Watertown, WI Facility
Legal Entity:WinkBeds LLC
16 CFR Part 1633 Prototype: WNK-135-HYB-2025Inspect →
Physical Tag Dimensions: 2.75" × 3.5" (Meets IABFLO 2.5" × 3.0" min)
What the tag number means
REG. NO. NC-009876 (WI)
Issuing State
NC (North Carolina)
Registry Sequence
#009876
Plant Location
WI (Wisconsin)
IABFLO 31-State Reciprocity: The issuing state (NC) participates in the Uniform Law Label system. This single registration permits lawful commercial distribution across all 31 regulated US bedding jurisdictions without duplicate state tags.
Specifications
Recorded specifications
Values and benchmarks recorded for this question.
| Specification | Measured value | Benchmark | Status |
|---|---|---|---|
| Hydrated Silica Structure | Amorphous Synthetic Silica (Non-Crystalline) | Non-Frangible Mineral | pass |
| Glass Fiber Structure | Crystalline / Vitreous Silicate Filaments | Shedding Hazard Warning | warning |
| Health Hazard Classification | Hydrated Silica: Non-Hazardous | Fiberglass: OSHA Respiratory Hazard | pass |
| Vitrification Behavior | Forms Vitrified Ceramic Char Shield | Effective Thermal Extinction | pass |
Standards reference: Benchmarks derived from ASTM D3574 (flexible cellular foam), CPSC 16 CFR 1633 (open flame flammability), and clinical capillary closing thresholds (32.0 mmHg).
Checklist
Consumer Safety & Chemical Verification Protocol
Step-by-step physical inspection procedure for flame barrier integrity and law label compliance.
- 01
Check Law Tag for Silica
Look for 'rayon treated with silica' or 'hydrated silica' on the law tag.
Watch for: If the tag lists 'glass fiber' or 'fiberglass', treat it as a high-risk shedding hazard.
- 02
Perform Darkroom Lens Inspection
Use a 10x jeweler loupe and flashlight to inspect surface fibers for clear needles.
Watch for: Never brush or agitate mattress ticking if sharp needles are visible.
- 03
Verify Manufacturer Disclosure
Contact the manufacturer to confirm whether silica is embedded in viscose yarn.
Watch for: Avoid ambiguous disclosures like 'proprietary mineral barrier'.
Sources
Sources for this answer
Read the source documents behind the thresholds, measurements, and policy details used here.
View source
U.S. Consumer Product Safety Commission (CPSC)
Standard for the Flammability of Mattress Sets
16 CFR Part 1633