☣️ UN 3499 • CLASS 9
UN 3499 — Capacitor, electric double layer
Placard: Miscellaneous. ERG Guide 171. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
UN 3499 is Capacitor, electric double layer, a Class 9 article assigned to ERG Guide 171. Main concerns are heat exposure, rupture, short circuit, electrolyte release and smoke from damaged units.
Hazard overview: Primary hazards include toxic exposure, fire or vapor ignition. Capacitor, electric double layer may release irritating, toxic or corrosive vapors when heated, spilled or involved in fire, so avoid contact, inhalation and incompatible materials.
Response guidance: For a UN 3499 incident, establish incident command, isolate the area, stay upwind and uphill, keep unauthorized personnel away, verify shipping papers/SDS and follow ERG 171. Use extinguishing, cooling, containment and decontamination tactics only when compatible with the material and local SOP.
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UN 3499 Quick Details
UN 3499
Product name: Capacitor, electric double layer
DOT Class: 9
Placard type: Miscellaneous
ERG Guide: 171 (check current ERG)
Initial isolation: ERG 171: isolate spill or leak area immediately for at least 25m in all directions; if fire involved, isolate 800m in all directions and consider initial evacuation for 800m
Common Hazards of UN 3499
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
Chemical Identity & Physical Properties
Solid device typically consisting of metal casing containing electrode materials, electrolyte solution, and separator membrane. May contain organic solvents or ionic liquids as electrolyte.
| Also known as | Electric double layer capacitorEDLCSupercapacitorUltracapacitorElectrochemical capacitor |
| Appearance | Solid device typically consisting of metal casing containing electrode materials, electrolyte solution, and separator membrane. May contain organic solvents or ionic liquids as electrolyte. |
| Flash Point | Not applicable (assembled device) |
| Boiling Point | Not applicable (assembled device) |
| Vapor Density | Not applicable (solid device) |
| Water Reactivity | Internal electrolyte may react with water if device is damaged or breached; intact devices show no significant water reactivity |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3499
Extinguishing Media
Dry chemical, CO2, sand, or water spray for external fires; avoid breaching device casing
PPE Requirements
⚠️ Level D minimum for intact units; Level C with respiratory protection if damaged units release organic vapors or electrolyte
Level D minimum for intact units; Level C with respiratory protection if damaged units release organic vapors or electrolyte
Isolation & Evacuation
ERG 171: isolate spill or leak area immediately for at least 25m in all directions; if fire involved, isolate 800m in all directions and consider initial evacuation for 800m
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 171).
First Actions for a UN 3499 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 3499 — Capacitor, electric double layerHAZMAT RADIO NOTE — UN 3499
Product: Capacitor, electric double layer
Class 9 / Miscellaneous / ERG 171
PPE: Level D minimum for intact units; Level C with respiratory protection if damaged units release organic vapors or electrolyte
ISOLATION: ERG 171: isolate spill or leak area immediately for at least 25m in all directions; if fire involved, isolate 800m in all directions and consider initial evacuation for 800m
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3499 — Capacitor, electric double layer
Class: 9 | Placard: Miscellaneous | ERG Guide: 171
Appearance: Solid device typically consisting of metal casing containing electrode materials, electrolyte solution, and separator membrane. May contain organic solvents or ionic liquids as electrolyte.
Water Reactivity: Internal electrolyte may react with water if device is damaged or breached; intact devices show no significant water reactivity
Extinguishing: Dry chemical, CO2, sand, or water spray for external fires; avoid breaching device casing
PPE: Level D minimum for intact units; Level C with respiratory protection if damaged units release organic vapors or electrolyte
Isolation: ERG 171: isolate spill or leak area immediately for at least 25m in all directions; if fire involved, isolate 800m in all directions and consider initial evacuation for 800m
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Some may be transported hot.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
• For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
SOURCE: allfirefighter.com/hazmat/un/capacitor-electric-double-layer-un-3499 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3499 Capacitor, electric double layer Cls9 ERG171 | allfirefighter.com/hazmat/un/capacitor-electric-double-layer-un-3499SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/capacitor-electric-double-layer-un-3499
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Frequently Asked Questions about UN 3499
UN 3499 is Capacitor, electric double layer, assigned to ERG Guide 171.
ERG Guide 171 applies for initial isolation, protective actions and first response guidance.
Yes. Capacitor, electric double layer can present a fire, combustion or vapor ignition hazard; keep it away from heat, sparks and flames.
Yes. Inhalation, ingestion, skin absorption or contaminated runoff may create serious health hazards.
Watch for heat, rupture, short circuit, electrolyte release, smoke and contaminated runoff from damaged units.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.