☣️ UN 3101 • CLASS 5
UN 3101 — Organic peroxide type B, liquid
Placard: Organic Peroxide. ERG Guide 146. 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 3101 Quick Details
UN 3101
Product name: Organic peroxide type B, liquid
DOT Class: 5
Placard type: Organic Peroxide
ERG Guide: 146 (check current ERG)
Initial isolation: ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
Common Hazards of UN 3101
- May explode from heat, shock, friction or contamination.
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- 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.
- Fire may produce irritating, corrosive and/or toxic gases.
- Ingestion or contact (skin, eyes) with substance may cause severe injury or burns.
Chemical Identity & Physical Properties
| Also known as | Organic peroxide type B liquidClass 5.2 organic peroxideExplosive organic peroxide liquidSelf-reactive peroxide |
| Appearance | Varies by specific compound; typically clear to colored liquid with mild or characteristic odor. Highly unstable organic peroxide formulation at room temperature. |
| Flash Point | Varies by formulation; typically low flash point or may ignite spontaneously |
| Boiling Point | Varies by specific peroxide compound; may decompose before boiling |
| Vapor Density | Varies by compound; typically heavier than air (>1) |
| Water Reactivity | Generally no violent reaction with water, but may be incompatible with certain formulations; avoid contamination |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3101
Extinguishing Media
Dry chemical, CO2 preferred; water fog or foam may be used from distance; avoid direct contact
PPE Requirements
⚠️ Level A or B required; full face SCBA mandatory; chemical-resistant suit; avoid all shock, friction, heat sources
Isolation & Evacuation
ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 146).
First Actions for a UN 3101 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 3101 — Organic peroxide type B, liquidHAZMAT RADIO NOTE — UN 3101
Product: Organic peroxide type B, liquid
Class 5 / Organic Peroxide / ERG 146
PPE: Level A or B required; full face SCBA mandatory; chemical-resistant suit; avoid all shock, friction, heat sources
ISOLATION: ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
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 3101 — Organic peroxide type B, liquid
Class: 5 | Placard: Organic Peroxide | ERG Guide: 146
Appearance: Varies by specific compound; typically clear to colored liquid with mild or characteristic odor. Highly unstable organic peroxide formulation at room temperature.
Water Reactivity: Generally no violent reaction with water, but may be incompatible with certain formulations; avoid contamination
Extinguishing: Dry chemical, CO2 preferred; water fog or foam may be used from distance; avoid direct contact
PPE: Level A or B required; full face SCBA mandatory; chemical-resistant suit; avoid all shock, friction, heat sources
Isolation: ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
— Key Hazards —
• May explode from heat, shock, friction or contamination.
• May ignite combustibles (wood, paper, oil, clothing, etc.).
• May be ignited by heat, sparks or flames.
— 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/3101 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3101 Organic peroxide type B, liquid Cls5 ERG146 | allfirefighter.com/hazmat/un/3101SMS / 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/3101
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Frequently Asked Questions about UN 3101
May explode from heat, shock, friction or contamination. May ignite combustibles (wood, paper, oil, clothing, etc.). 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. Fire may produce irritating, corrosive and/or toxic gases. Ingestion or contact (skin, eyes) with substance may cause severe injury or burns.
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 or B required; full face SCBA mandatory; chemical-resistant suit; avoid all shock, friction, heat sources
Water reactivity: Generally no violent reaction with water, but may be incompatible with certain formulations; avoid contamination. Recommended extinguishing: Dry chemical, CO2 preferred; water fog or foam may be used from distance; avoid direct contact.
ERG Guide 146 recommendation: ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 146 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.