☣️ UN 3224 • CLASS 4
UN 3224 — Self-reactive solid type C
Placard: Flammable Solid. ERG Guide 149. 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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UN 3224 Quick Details
UN 3224
Product name: Self-reactive solid type C
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 149 (check current ERG)
Initial isolation: ERG 149: isolate 50m in all directions; for fire, isolate 800m and consider evacuation in downwind direction; protect from heat, friction, and contamination
Common Hazards of UN 3224
- Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
- May be ignited by heat, sparks or flames.
- Some may decompose explosively when heated or involved in a fire.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- May burn violently. Decomposition or polymerization may be self-accelerating and produce large
- Vapors or dust may form explosive mixtures with air.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
- May produce irritating, toxic and/or corrosive gases.
Chemical Identity & Physical Properties
| Also known as | Self-reactive solid type COrganic peroxide type C solidSelf-accelerating decomposition materialSADM solid type C |
| Appearance | Solid material at room temperature, variable color depending on specific formulation. May be crystalline, granular, or powder form. Generally organic compounds with reactive functional groups. |
| Flash Point | Not applicable (self-reactive solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Generally no significant reaction with water, but may release heat; avoid large quantities of water which may spread decomposition |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3224
Extinguishing Media
Dry chemical, sand, or inert material preferred; avoid water streams; CO2 may be used for small fires
PPE Requirements
⚠️ Level B minimum recommended; SCBA required in all fire or decomposition scenarios; heat-resistant protective clothing if exposed to fire
Isolation & Evacuation
ERG 149: isolate 50m in all directions; for fire, isolate 800m and consider evacuation in downwind direction; protect from heat, friction, and contamination
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 149).
First Actions for a UN 3224 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- 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
- Consider initial evacuation for at least 250 meters (800 feet) in all directions.
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📋 Copy & Share Field Card
UN 3224 — Self-reactive solid type CHAZMAT RADIO NOTE — UN 3224
Product: Self-reactive solid type C
Class 4 / Flammable Solid / ERG 149
PPE: Level B minimum recommended; SCBA required in all fire or decomposition scenarios; heat-resistant protective clothing if exposed to fire
ISOLATION: ERG 149: isolate 50m in all directions; for fire, isolate 800m and consider evacuation in downwind direction; protect from heat, friction, and contamination
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 3224 — Self-reactive solid type C
Class: 4 | Placard: Flammable Solid | ERG Guide: 149
Appearance: Solid material at room temperature, variable color depending on specific formulation. May be crystalline, granular, or powder form. Generally organic compounds with reactive functional groups.
Water Reactivity: Generally no significant reaction with water, but may release heat; avoid large quantities of water which may spread decomposition
Extinguishing: Dry chemical, sand, or inert material preferred; avoid water streams; CO2 may be used for small fires
PPE: Level B minimum recommended; SCBA required in all fire or decomposition scenarios; heat-resistant protective clothing if exposed to fire
Isolation: ERG 149: isolate 50m in all directions; for fire, isolate 800m and consider evacuation in downwind direction; protect from heat, friction, and contamination
— Key Hazards —
• Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
• May be ignited by heat, sparks or flames.
• Some may decompose explosively when heated or involved in a fire.
— 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.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/3224 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3224 Self-reactive solid type C Cls4 ERG149 | allfirefighter.com/hazmat/un/3224SMS / 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/3224
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Frequently Asked Questions about UN 3224
Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical May be ignited by heat, sparks or flames. Some may decompose explosively when heated or involved in a fire. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. May burn violently. Decomposition or polymerization may be self-accelerating and produce large Vapors or dust may form explosive mixtures with air. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or May produce irritating, toxic and/or corrosive gases.
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 recommended; SCBA required in all fire or decomposition scenarios; heat-resistant protective clothing if exposed to fire
Water reactivity: Generally no significant reaction with water, but may release heat; avoid large quantities of water which may spread decomposition. Recommended extinguishing: Dry chemical, sand, or inert material preferred; avoid water streams; CO2 may be used for small fires.
ERG Guide 149 recommendation: ERG 149: isolate 50m in all directions; for fire, isolate 800m and consider evacuation in downwind direction; protect from heat, friction, and contamination
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 149 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.