☣️ UN 3101 • CLASS 5

Organic peroxide type B, liquid

Placard: Organic Peroxide. 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 3101
Class: 5
Placard type: Organic Peroxide
ERG: Guide 146 (check current ERG)
Isolation: ERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
Chemical & Response Details
Also known asOrganic peroxide type B liquidClass 5.2 organic peroxideExplosive organic peroxide liquidSelf-reactive peroxide
AppearanceVaries by specific compound; typically clear to colored liquid with mild or characteristic odor. Highly unstable organic peroxide formulation at room temperature.
Flash PointVaries by formulation; typically low flash point or may ignite spontaneously
Boiling PointVaries by specific peroxide compound; may decompose before boiling
Vapor DensityVaries by compound; typically heavier than air (>1)
Water ReactivityGenerally no violent reaction with water, but may be incompatible with certain formulations; avoid contamination
ExtinguishingDry 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
IsolationERG 146: isolate 500m all directions; evacuate 800m downwind if tank/railcar involved; consider explosive potential
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • 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.
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 3101 — Organic peroxide type B, liquid
HAZMAT 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.

SMS WhatsApp
=== 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.

SMS (short)
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
Related UN numbers (same class)
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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FAQ

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

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.