☣️ UN 3112 • CLASS 5
UN 3112 — Organic peroxide type B, solid, temperature controlled
Placard: Organic Peroxide. ERG Guide 148. 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 3112 Quick Details
UN 3112
Product name: Organic peroxide type B, solid, temperature controlled
DOT Class: 5
Placard type: Organic Peroxide
ERG Guide: 148 (check current ERG)
Initial isolation: ERG 148: Isolate 800m all directions initially; evacuate 1600m in all directions if tank/rail car involved in fire; temperature monitoring critical; maintain temperature control to prevent runaway decomposition
Common Hazards of UN 3112
- May explode from heat, contamination or loss of temperature control.
- These materials are particularly sensitive to temperature rises. Above a given "Control Temperature"
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- May ignite spontaneously if exposed to air.
- May be ignited by heat, sparks or flames.
- May burn rapidly with flare-burning effect.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
Chemical Identity & Physical Properties
| Also known as | Organic peroxide type B solidTemperature controlled organic peroxideSelf-reactive solid type BThermally unstable organic peroxide solid |
| Appearance | Solid organic peroxide requiring temperature control during transport. Typically white to off-white crystalline or granular solid with slight organic odor. Extremely temperature-sensitive and shock-sensitive explosive material. |
| Flash Point | Not applicable (self-reactive explosive solid) |
| Boiling Point | Not applicable (decomposes violently before boiling) |
| Vapor Density | Not applicable (solid, non-volatile) |
| Water Reactivity | May react with water releasing heat and oxygen; avoid water contamination which can trigger decomposition |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3112
Extinguishing Media
Do not use water or foam; use dry chemical, CO2, or sand only; cooling with flooding amounts of water from distance may be necessary in large fires
PPE Requirements
⚠️ Level A required for spills; full face SCBA mandatory; heat-resistant structural firefighting gear minimum; maintain distance due to explosion hazard
Isolation & Evacuation
ERG 148: Isolate 800m all directions initially; evacuate 1600m in all directions if tank/rail car involved in fire; temperature monitoring critical; maintain temperature control to prevent runaway decomposition
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 148).
First Actions for a UN 3112 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 3112 — Organic peroxide type B, solid, temperatHAZMAT RADIO NOTE — UN 3112
Product: Organic peroxide type B, solid, temperature controlled
Class 5 / Organic Peroxide / ERG 148
PPE: Level A required for spills; full face SCBA mandatory; heat-resistant structural firefighting gear minimum; maintain distance due to explosion hazard
ISOLATION: ERG 148: Isolate 800m all directions initially; evacuate 1600m in all directions if tank/rail car involved in fire; temperature monitoring critical; maintain temperature control to prevent runaway decomposition
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 3112 — Organic peroxide type B, solid, temperature controlled
Class: 5 | Placard: Organic Peroxide | ERG Guide: 148
Appearance: Solid organic peroxide requiring temperature control during transport. Typically white to off-white crystalline or granular solid with slight organic odor. Extremely temperature-sensitive and shock-sensitive explosive material.
Water Reactivity: May react with water releasing heat and oxygen; avoid water contamination which can trigger decomposition
Extinguishing: Do not use water or foam; use dry chemical, CO2, or sand only; cooling with flooding amounts of water from distance may be necessary in large fires
PPE: Level A required for spills; full face SCBA mandatory; heat-resistant structural firefighting gear minimum; maintain distance due to explosion hazard
Isolation: ERG 148: Isolate 800m all directions initially; evacuate 1600m in all directions if tank/rail car involved in fire; temperature monitoring critical; maintain temperature control to prevent runaway decomposition
— Key Hazards —
• May explode from heat, contamination or loss of temperature control.
• These materials are particularly sensitive to temperature rises. Above a given "Control Temperature"
• May ignite combustibles (wood, paper, oil, clothing, etc.).
— 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/3112 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3112 Organic peroxide type B, solid, temperature controlled Cls5 ERG148 | allfirefighter.com/hazmat/un/3112SMS / 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/3112
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Frequently Asked Questions about UN 3112
May explode from heat, contamination or loss of temperature control. These materials are particularly sensitive to temperature rises. Above a given "Control Temperature" May ignite combustibles (wood, paper, oil, clothing, etc.). May ignite spontaneously if exposed to air. May be ignited by heat, sparks or flames. May burn rapidly with flare-burning effect. Containers may explode when heated. Runoff may create fire or explosion hazard.
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 A required for spills; full face SCBA mandatory; heat-resistant structural firefighting gear minimum; maintain distance due to explosion hazard
Water reactivity: May react with water releasing heat and oxygen; avoid water contamination which can trigger decomposition. Recommended extinguishing: Do not use water or foam; use dry chemical, CO2, or sand only; cooling with flooding amounts of water from distance may be necessary in large fires.
ERG Guide 148 recommendation: ERG 148: Isolate 800m all directions initially; evacuate 1600m in all directions if tank/rail car involved in fire; temperature monitoring critical; maintain temperature control to prevent runaway decomposition
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 148 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.