☣️ UN 3476 • CLASS 4
Fuel cell cartridges contained in equipment, containing waterreactive substances
Placard: Dangerous When Wet. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 3476
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: isolate spill 25m all directions; if fire, evacuate 800m downwind; keep containers dry
Chemical & Response Details
| Also known as | Fuel cell cartridges with water-reactive materialsEquipment-integrated fuel cell cartridgesWater-reactive fuel cell systems |
| Appearance | Sealed cartridges or containers integrated within equipment, containing water-reactive substances that may be solid or liquid. Appearance varies depending on the specific water-reactive material contained. |
| Flash Point | Not applicable (water-reactive material) |
| Boiling Point | Not applicable (varies by contained substance) |
| Vapor Density | Not applicable (contained system) |
| Water Reactivity | Reacts with water to produce flammable gases; may ignite spontaneously on contact with water or moist air; some formulations react violently or explosively |
| Extinguishing | Dry chemical, dry sand, soda ash; DO NOT use water, foam, or CO2 |
| PPE | ⚠️ Level B minimum; SCBA required; chemical-resistant suit for spills; avoid moisture exposure during handling |
| Isolation | ERG 138: isolate spill 25m all directions; if fire, evacuate 800m downwind; keep containers dry |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Produce flammable gases on contact with water.
- May ignite on contact with water or moist air.
- Some react vigorously or explosively on contact with water.
- May be ignited by heat, sparks or flames.
- May re-ignite after fire is extinguished.
- Some are transported in highly flammable liquids.
- Runoff may create fire or explosion hazard.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
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.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 3476 — Fuel cell cartridges contained in equipm HAZMAT RADIO NOTE — UN 3476
Product: Fuel cell cartridges contained in equipment, containing waterreactive substances
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum; SCBA required; chemical-resistant suit for spills; avoid moisture exposure during handling
ISOLATION: ERG 138: isolate spill 25m all directions; if fire, evacuate 800m downwind; keep containers dry
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 3476 — Fuel cell cartridges contained in equipment, containing waterreactive substances
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Sealed cartridges or containers integrated within equipment, containing water-reactive substances that may be solid or liquid. Appearance varies depending on the specific water-reactive material contained.
Water Reactivity: Reacts with water to produce flammable gases; may ignite spontaneously on contact with water or moist air; some formulations react violently or explosively
Extinguishing: Dry chemical, dry sand, soda ash; DO NOT use water, foam, or CO2
PPE: Level B minimum; SCBA required; chemical-resistant suit for spills; avoid moisture exposure during handling
Isolation: ERG 138: isolate spill 25m all directions; if fire, evacuate 800m downwind; keep containers dry
— Key Hazards —
• Produce flammable gases on contact with water.
• May ignite on contact with water or moist air.
• Some react vigorously or explosively on contact with water.
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/3476 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3476 Fuel cell cartridges contained in equipment, containing waterreactive substances Cls4 ERG138 | allfirefighter.com/hazmat/un/3476SMS / 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/3476
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FAQ
Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
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; SCBA required; chemical-resistant suit for spills; avoid moisture exposure during handling
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 138 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.