☣️ UN 2741 • CLASS 5
UN 2741 — Barium hypochlorite, with more than 22% available chlorine
Placard: Oxidizer. ERG Guide 141. 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 2741 Quick Details
UN 2741
Product name: Barium hypochlorite, with more than 22% available chlorine
DOT Class: 5
Placard type: Oxidizer
ERG Guide: 141 (check current ERG)
Initial isolation: ERG 141: isolate 100m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Common Hazards of UN 2741
- These substances will accelerate burning when involved in a fire.
- May explode from heat or contamination.
- Some may burn rapidly.
- Some will react explosively with hydrocarbons (fuels).
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- Toxic by ingestion.
Chemical Identity & Physical Properties
| Also known as | Barium hypochloriteHypochlorous acid barium saltBarium chlorite hypochlorite |
| CAS Number | 13477-10-6 |
| Appearance | White to grayish-white granular powder or solid with a chlorine-like odor. Oxidizing solid that decomposes in moist air. |
| Flash Point | Not applicable (oxidizing solid, non-flammable but accelerates combustion) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Decomposes slowly in water, releasing oxygen and forming barium hydroxide; avoid large amounts of water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2741
Extinguishing Media
Dry chemical, sand, or dry earth; do not use water except in large flooding quantities; avoid organic materials
PPE Requirements
⚠️ Level B minimum with full face SCBA; chemical-resistant suit; avoid skin contact due to oxidizer and caustic properties
Isolation & Evacuation
ERG 141: isolate 100m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 141).
First Actions for a UN 2741 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.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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UN 2741 — Barium hypochlorite, with more than 22%HAZMAT RADIO NOTE — UN 2741
Product: Barium hypochlorite, with more than 22% available chlorine
Class 5 / Oxidizer / ERG 141
PPE: Level B minimum with full face SCBA; chemical-resistant suit; avoid skin contact due to oxidizer and caustic properties
ISOLATION: ERG 141: isolate 100m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
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 2741 — Barium hypochlorite, with more than 22% available chlorine
Class: 5 | Placard: Oxidizer | ERG Guide: 141
Appearance: White to grayish-white granular powder or solid with a chlorine-like odor. Oxidizing solid that decomposes in moist air.
Water Reactivity: Decomposes slowly in water, releasing oxygen and forming barium hydroxide; avoid large amounts of water
Extinguishing: Dry chemical, sand, or dry earth; do not use water except in large flooding quantities; avoid organic materials
PPE: Level B minimum with full face SCBA; chemical-resistant suit; avoid skin contact due to oxidizer and caustic properties
Isolation: ERG 141: isolate 100m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• May explode from heat or contamination.
• Some may burn rapidly.
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/2741 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2741 Barium hypochlorite, with more than 22% available chlorine Cls5 ERG141 | allfirefighter.com/hazmat/un/2741SMS / 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/2741
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Frequently Asked Questions about UN 2741
These substances will accelerate burning when involved in a fire. May explode from heat or contamination. Some may burn rapidly. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard. Toxic by ingestion.
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 with full face SCBA; chemical-resistant suit; avoid skin contact due to oxidizer and caustic properties
Water reactivity: Decomposes slowly in water, releasing oxygen and forming barium hydroxide; avoid large amounts of water. Recommended extinguishing: Dry chemical, sand, or dry earth; do not use water except in large flooding quantities; avoid organic materials.
ERG Guide 141 recommendation: ERG 141: isolate 100m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 141 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.