☣️ UN 3225 • CLASS 4
Self-reactive liquid type D
Placard: Flammable Solid. 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 3225
Class: 4
Placard type: Flammable Solid
ERG: Guide 149 (check current ERG)
Isolation: ERG 149: isolate spill area immediate 50m all directions; fire: isolate 800m all directions, consider evacuation 800m radius; treat as potential explosion hazard
Chemical & Response Details
| Also known as | Organic peroxide type D liquidSelf-reactive substance type DPolymerizable liquidSelf-heating organic liquid |
| Appearance | Variable appearance depending on specific compound; typically a clear to colored liquid at room temperature. May have characteristic chemical odor. Prone to self-accelerating decomposition or polymerization. |
| Flash Point | Varies by formulation, typically <60C (140F) for most type D substances |
| Boiling Point | Varies by specific compound, typically 100-250C (212-482F) range |
| Vapor Density | Typically >1 (heavier than air), varies by specific formulation |
| Water Reactivity | Generally no violent reaction with water, but water may not control decomposition; some formulations may react with water depending on composition |
| Extinguishing | Alcohol-resistant foam, dry chemical, CO2; flooding quantities of water may help cool containers; avoid fine water spray that may not penetrate effectively |
| PPE | ⚠️ Level B minimum with SCBA required; chemical-resistant suit for spill response; maintain distance due to explosive decomposition potential; no skin contact |
| Isolation | ERG 149: isolate spill area immediate 50m all directions; fire: isolate 800m all directions, consider evacuation 800m radius; treat as potential explosion hazard |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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.
- 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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UN 3225 — Self-reactive liquid type D HAZMAT RADIO NOTE — UN 3225
Product: Self-reactive liquid type D
Class 4 / Flammable Solid / ERG 149
PPE: Level B minimum with SCBA required; chemical-resistant suit for spill response; maintain distance due to explosive decomposition potential; no skin contact
ISOLATION: ERG 149: isolate spill area immediate 50m all directions; fire: isolate 800m all directions, consider evacuation 800m radius; treat as potential explosion hazard
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 3225 — Self-reactive liquid type D
Class: 4 | Placard: Flammable Solid | ERG Guide: 149
Appearance: Variable appearance depending on specific compound; typically a clear to colored liquid at room temperature. May have characteristic chemical odor. Prone to self-accelerating decomposition or polymerization.
Water Reactivity: Generally no violent reaction with water, but water may not control decomposition; some formulations may react with water depending on composition
Extinguishing: Alcohol-resistant foam, dry chemical, CO2; flooding quantities of water may help cool containers; avoid fine water spray that may not penetrate effectively
PPE: Level B minimum with SCBA required; chemical-resistant suit for spill response; maintain distance due to explosive decomposition potential; no skin contact
Isolation: ERG 149: isolate spill area immediate 50m all directions; fire: isolate 800m all directions, consider evacuation 800m radius; treat as potential explosion hazard
— 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/3225 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3225 Self-reactive liquid type D Cls4 ERG149 | allfirefighter.com/hazmat/un/3225SMS / 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/3225
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FAQ
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 with SCBA required; chemical-resistant suit for spill response; maintain distance due to explosive decomposition potential; no skin contact
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.