☣️ UN 3235 • CLASS 4
UN 3235 — Self-reactive liquid type D, temperature controlled
Placard: Flammable Solid. ERG Guide 150. 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 3235 Quick Details
UN 3235
Product name: Self-reactive liquid type D, temperature controlled
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 150 (check current ERG)
Initial isolation: ERG 150: isolate 50m all directions initially; if fire or decomposition, isolate 800m and consider evacuation 1600m downwind; maintain control temperature per shipping papers
Common Hazards of UN 3235
- Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
- Self-accelerating decomposition may occur if the specific "control temperature" is not maintained.
- These materials are particularly sensitive to temperature rises. Above a given "Control Temperature"
- May be ignited by heat, sparks or flames.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Some may decompose 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.
Chemical Identity & Physical Properties
| Also known as | Self-reactive liquid type DTemperature controlled self-reactive substanceOrganic peroxide derivative type DSelf-accelerating decomposition substance |
| Appearance | Typically a clear to pale yellow liquid with mild to sharp odor depending on specific formulation. Physical state is liquid at room temperature but requires temperature control for stability. |
| Flash Point | Varies by formulation, typically 60-93C (140-200F) for Type D materials |
| Boiling Point | Varies by specific formulation, typically 150-250C (302-482F) |
| Vapor Density | Typically 3-5 (heavier than air), varies by specific compound |
| Water Reactivity | Generally no significant reaction with water, but water may not effectively cool during decomposition |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3235
Extinguishing Media
Dry chemical, CO2, water spray for cooling only; foam may be ineffective during active decomposition
PPE Requirements
⚠️ Level B minimum with SCBA required; thermal protection if decomposition has begun; maintain temperature monitoring equipment
Isolation & Evacuation
ERG 150: isolate 50m all directions initially; if fire or decomposition, isolate 800m and consider evacuation 1600m downwind; maintain control temperature per shipping papers
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 150).
First Actions for a UN 3235 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 3235 — Self-reactive liquid type D, temperatureHAZMAT RADIO NOTE — UN 3235
Product: Self-reactive liquid type D, temperature controlled
Class 4 / Flammable Solid / ERG 150
PPE: Level B minimum with SCBA required; thermal protection if decomposition has begun; maintain temperature monitoring equipment
ISOLATION: ERG 150: isolate 50m all directions initially; if fire or decomposition, isolate 800m and consider evacuation 1600m downwind; maintain control temperature per shipping papers
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 3235 — Self-reactive liquid type D, temperature controlled
Class: 4 | Placard: Flammable Solid | ERG Guide: 150
Appearance: Typically a clear to pale yellow liquid with mild to sharp odor depending on specific formulation. Physical state is liquid at room temperature but requires temperature control for stability.
Water Reactivity: Generally no significant reaction with water, but water may not effectively cool during decomposition
Extinguishing: Dry chemical, CO2, water spray for cooling only; foam may be ineffective during active decomposition
PPE: Level B minimum with SCBA required; thermal protection if decomposition has begun; maintain temperature monitoring equipment
Isolation: ERG 150: isolate 50m all directions initially; if fire or decomposition, isolate 800m and consider evacuation 1600m downwind; maintain control temperature per shipping papers
— Key Hazards —
• Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
• Self-accelerating decomposition may occur if the specific "control temperature" is not maintained.
• These materials are particularly sensitive to temperature rises. Above a given "Control Temperature"
— 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/3235 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3235 Self-reactive liquid type D, temperature controlled Cls4 ERG150 | allfirefighter.com/hazmat/un/3235SMS / 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/3235
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Frequently Asked Questions about UN 3235
Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical Self-accelerating decomposition may occur if the specific "control temperature" is not maintained. These materials are particularly sensitive to temperature rises. Above a given "Control Temperature" May be ignited by heat, sparks or flames. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Some may decompose 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.
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; thermal protection if decomposition has begun; maintain temperature monitoring equipment
Water reactivity: Generally no significant reaction with water, but water may not effectively cool during decomposition. Recommended extinguishing: Dry chemical, CO2, water spray for cooling only; foam may be ineffective during active decomposition.
ERG Guide 150 recommendation: ERG 150: isolate 50m all directions initially; if fire or decomposition, isolate 800m and consider evacuation 1600m downwind; maintain control temperature per shipping papers
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 150 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.