☣️ UN 3479 • CLASS 2

Fuel cell cartridges contained in equipment, containing hydrogen in metal hydride

Placard: Flammable Gas. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.

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⚠️ 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.
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Quick details
UN 3479
Class: 2
Placard type: Flammable Gas
ERG: Guide 115 (check current ERG)
Isolation: ERG 115: Initial isolation 100m all directions; if fire or spill is large, isolate 800m all directions; evacuate area and deny entry
Chemical & Response Details
Also known asFuel cell cartridges with metal hydrideHydrogen metal hydride fuel cellsMetal hydride hydrogen storage cartridges
AppearanceSolid metal hydride cartridges containing absorbed hydrogen gas. Cartridges are typically gray or metallic in color and housed in equipment. Hydrogen is stored in the metal lattice structure and released when heated.
Flash PointNot applicable (hydrogen gas is extremely flammable with autoignition temperature 500C/932F)
Boiling PointNot applicable (hydrogen boiling point -253C/-423F, stored as metal hydride)
Vapor DensityNot applicable when stored; released hydrogen is 0.07 (much lighter than air)
Water ReactivityMetal hydrides may react with water to release hydrogen gas, increasing fire hazard
ExtinguishingCO2, dry chemical, or dry sand for metal fires; regular foam ineffective; do not use water on burning metal hydride
PPE⚠️ Level B minimum with SCBA; full face shield and thermal protection for fire; monitor for hydrogen accumulation in confined spaces
IsolationERG 115: Initial isolation 100m all directions; if fire or spill is large, isolate 800m all directions; evacuate area and deny entry
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • EXTREMELY FLAMMABLE.
  • Will be easily ignited by heat, sparks or flames.
  • Will form explosive mixtures with air.
  • Vapors from liquefied gas are initially heavier than air and spread along ground.
  • Vapors may travel to source of ignition and flash back.
  • Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
  • Containers may explode when heated.
  • Ruptured cylinders may rocket.
First actions (field-minded)
  • CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
  • Keep unauthorized personnel away.
  • Stay upwind, uphill and/or upstream.
  • Many gases are heavier than air and will spread along the ground and collect in low or confined areas
  • Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
  • Consider initial downwind evacuation for at least 800 meters (1/2 mile).
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UN 3479 — Fuel cell cartridges contained in equipm
HAZMAT RADIO NOTE — UN 3479 Product: Fuel cell cartridges contained in equipment, containing hydrogen in metal hydride Class 2 / Flammable Gas / ERG 115 PPE: Level B minimum with SCBA; full face shield and thermal protection for fire; monitor for hydrogen accumulation in confined spaces ISOLATION: ERG 115: Initial isolation 100m all directions; if fire or spill is large, isolate 800m all directions; evacuate area and deny entry ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 3479 — Fuel cell cartridges contained in equipment, containing hydrogen in metal hydride Class: 2 | Placard: Flammable Gas | ERG Guide: 115 Appearance: Solid metal hydride cartridges containing absorbed hydrogen gas. Cartridges are typically gray or metallic in color and housed in equipment. Hydrogen is stored in the metal lattice structure and released when heated. Water Reactivity: Metal hydrides may react with water to release hydrogen gas, increasing fire hazard Extinguishing: CO2, dry chemical, or dry sand for metal fires; regular foam ineffective; do not use water on burning metal hydride PPE: Level B minimum with SCBA; full face shield and thermal protection for fire; monitor for hydrogen accumulation in confined spaces Isolation: ERG 115: Initial isolation 100m all directions; if fire or spill is large, isolate 800m all directions; evacuate area and deny entry — Key Hazards — • EXTREMELY FLAMMABLE. • Will be easily ignited by heat, sparks or flames. • Will form explosive mixtures with air. — First Actions — • CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper • Keep unauthorized personnel away. • Stay upwind, uphill and/or upstream. • Many gases are heavier than air and will spread along the ground and collect in low or confined areas SOURCE: allfirefighter.com/hazmat/un/3479 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.

SMS (short)
UN3479 Fuel cell cartridges contained in equipment, containing hydrogen in metal hydride Cls2 ERG115 | allfirefighter.com/hazmat/un/3479SMS / 160 CHAR

Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.

⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/3479
Related UN numbers (same class)
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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FAQ

EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket.

CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.

Level B minimum with SCBA; full face shield and thermal protection for fire; monitor for hydrogen accumulation in confined spaces

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 115 and your department SOP/SOG for incident-specific protective actions.
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.