☣️ UN 3111 • CLASS 5
UN 3111 — Organic peroxide type B, liquid, 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 3111 Quick Details
UN 3111
Product name: Organic peroxide type B, liquid, temperature controlled
DOT Class: 5
Placard type: Organic Peroxide
ERG Guide: 148 (check current ERG)
Initial isolation: ERG 148: Isolate spill area immediately for at least 100m in all directions; if tank/container involved in fire, isolate 800m in all directions and consider evacuation; loss of temperature control may lead to spontaneous decomposition and explosion
Common Hazards of UN 3111
- 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 liquidTemperature-controlled organic peroxideSelf-reactive liquid type BThermally unstable organic peroxide |
| Appearance | Varies by specific peroxide formulation; typically clear to pale yellow liquids with characteristic peroxide odor. These are highly reactive organic compounds containing the peroxy (-O-O-) functional group that are stored and transported under controlled temperature conditions. |
| Flash Point | Not applicable (self-reactive material, does not require ignition source) |
| Boiling Point | Varies by formulation; decomposes exothermically before reaching normal boiling point |
| Vapor Density | Typically >1 (heavier than air), but varies by specific peroxide compound |
| Water Reactivity | Generally stable in water but avoid contamination; water may be used for cooling containers in fire situations |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3111
Extinguishing Media
Water spray to keep containers cool, CO2 or dry chemical for small fires; DO NOT use foam or halogenated agents which may accelerate decomposition
PPE Requirements
⚠️ Level A required for spill response; full encapsulation with SCBA; thermal protective clothing if fire involved; maintain temperature control at all times
Isolation & Evacuation
ERG 148: Isolate spill area immediately for at least 100m in all directions; if tank/container involved in fire, isolate 800m in all directions and consider evacuation; loss of temperature control may lead to spontaneous decomposition and explosion
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 148).
First Actions for a UN 3111 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 3111 — Organic peroxide type B, liquid, temperaHAZMAT RADIO NOTE — UN 3111
Product: Organic peroxide type B, liquid, temperature controlled
Class 5 / Organic Peroxide / ERG 148
PPE: Level A required for spill response; full encapsulation with SCBA; thermal protective clothing if fire involved; maintain temperature control at all times
ISOLATION: ERG 148: Isolate spill area immediately for at least 100m in all directions; if tank/container involved in fire, isolate 800m in all directions and consider evacuation; loss of temperature control may lead to spontaneous decomposition and explosion
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 3111 — Organic peroxide type B, liquid, temperature controlled
Class: 5 | Placard: Organic Peroxide | ERG Guide: 148
Appearance: Varies by specific peroxide formulation; typically clear to pale yellow liquids with characteristic peroxide odor. These are highly reactive organic compounds containing the peroxy (-O-O-) functional group that are stored and transported under controlled temperature conditions.
Water Reactivity: Generally stable in water but avoid contamination; water may be used for cooling containers in fire situations
Extinguishing: Water spray to keep containers cool, CO2 or dry chemical for small fires; DO NOT use foam or halogenated agents which may accelerate decomposition
PPE: Level A required for spill response; full encapsulation with SCBA; thermal protective clothing if fire involved; maintain temperature control at all times
Isolation: ERG 148: Isolate spill area immediately for at least 100m in all directions; if tank/container involved in fire, isolate 800m in all directions and consider evacuation; loss of temperature control may lead to spontaneous decomposition and explosion
— 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/3111 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3111 Organic peroxide type B, liquid, temperature controlled Cls5 ERG148 | allfirefighter.com/hazmat/un/3111SMS / 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/3111
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Frequently Asked Questions about UN 3111
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 spill response; full encapsulation with SCBA; thermal protective clothing if fire involved; maintain temperature control at all times
Water reactivity: Generally stable in water but avoid contamination; water may be used for cooling containers in fire situations. Recommended extinguishing: Water spray to keep containers cool, CO2 or dry chemical for small fires; DO NOT use foam or halogenated agents which may accelerate decomposition.
ERG Guide 148 recommendation: ERG 148: Isolate spill area immediately for at least 100m in all directions; if tank/container involved in fire, isolate 800m in all directions and consider evacuation; loss of temperature control may lead to spontaneous decomposition and explosion
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.