☣️ UN 3103 • CLASS 5

Organic peroxide type C, 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 3103
Class: 5
Placard type: Organic Peroxide
ERG: Guide 146 (check current ERG)
Isolation: ERG 146: Initial isolation 100m all directions; protective action distance 300m downwind for small spill daytime, 800m for large spill or nighttime; evacuate area if fire involves significant quantities
Chemical & Response Details
Also known asOrganic peroxide type C liquidClass 5.2 organic peroxidePeroxidic compound liquidType C peroxide formulation
AppearanceVaries by specific formulation; typically clear to pale yellow liquid with mild characteristic odor. Organic peroxides are thermally unstable oxidizing agents at room temperature.
Flash PointVaries by formulation, typically 50-80°C (122-176°F) for Type C
Boiling PointVaries by formulation, typically 100-200°C (212-392°F)
Vapor DensityTypically 3-6 (heavier than air, varies by specific peroxide)
Water ReactivityGenerally no violent reaction with water, but may decompose; some formulations may be water-reactive depending on composition
ExtinguishingAlcohol-resistant foam, CO2, dry chemical; large fires may require flooding quantities of water from distance
PPE⚠️ Level B minimum required; SCBA with full face piece; chemical-resistant suit; avoid all sources of ignition; explosion risk mandates blast protection considerations
IsolationERG 146: Initial isolation 100m all directions; protective action distance 300m downwind for small spill daytime, 800m for large spill or nighttime; evacuate area if fire involves significant quantities
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 3103 — Organic peroxide type C, liquid
HAZMAT RADIO NOTE — UN 3103 Product: Organic peroxide type C, liquid Class 5 / Organic Peroxide / ERG 146 PPE: Level B minimum required; SCBA with full face piece; chemical-resistant suit; avoid all sources of ignition; explosion risk mandates blast protection considerations ISOLATION: ERG 146: Initial isolation 100m all directions; protective action distance 300m downwind for small spill daytime, 800m for large spill or nighttime; evacuate area if fire involves significant quantities 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 3103 — Organic peroxide type C, liquid Class: 5 | Placard: Organic Peroxide | ERG Guide: 146 Appearance: Varies by specific formulation; typically clear to pale yellow liquid with mild characteristic odor. Organic peroxides are thermally unstable oxidizing agents at room temperature. Water Reactivity: Generally no violent reaction with water, but may decompose; some formulations may be water-reactive depending on composition Extinguishing: Alcohol-resistant foam, CO2, dry chemical; large fires may require flooding quantities of water from distance PPE: Level B minimum required; SCBA with full face piece; chemical-resistant suit; avoid all sources of ignition; explosion risk mandates blast protection considerations Isolation: ERG 146: Initial isolation 100m all directions; protective action distance 300m downwind for small spill daytime, 800m for large spill or nighttime; evacuate area if fire involves significant quantities — 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/3103 | 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)
UN3103 Organic peroxide type C, liquid Cls5 ERG146 | allfirefighter.com/hazmat/un/3103SMS / 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/3103
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 B minimum required; SCBA with full face piece; chemical-resistant suit; avoid all sources of ignition; explosion risk mandates blast protection considerations

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.