☣️ UN 1451 • CLASS 5
UN 1451 — Caesium nitrate
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 1451 Quick Details
UN 1451
Product name: Caesium nitrate
DOT Class: 5
Placard type: Oxidizer
ERG Guide: 140 (check current ERG)
Initial isolation: ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill isolate 800m and evacuate downwind
Common Hazards of UN 1451
- These substances will accelerate burning when involved in a fire.
- Some may decompose explosively when heated or involved in a fire.
- May explode from heat or contamination.
- 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.
- Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or
Chemical Identity & Physical Properties
| Also known as | Cesium nitrateNitric acid cesium saltCesium(I) nitrateCaesium mononitrate |
| CAS Number | 7789-18-6 |
| Appearance | White or colorless crystalline solid, odorless. Hygroscopic powder or crystals at room temperature. |
| Flash Point | Not applicable (oxidizing solid, non-flammable but supports combustion) |
| Boiling Point | Decomposes at 414C (777F) before boiling |
| Vapor Density | Not applicable (solid with negligible vapor pressure) |
| Water Reactivity | Soluble in water without hazardous reaction, but solution may be corrosive |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1451
Extinguishing Media
Water spray, dry chemical, CO2; avoid organic materials and combustibles near oxidizer
PPE Requirements
⚠️ Level C minimum for handling; SCBA and full protective clothing if fire involved or decomposition occurring
Isolation & Evacuation
ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill isolate 800m and evacuate downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 140).
First Actions for a UN 1451 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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📋 Copy & Share Field Card
UN 1451 — Caesium nitrateHAZMAT RADIO NOTE — UN 1451
Product: Caesium nitrate
Class 5 / Oxidizer / ERG 140
PPE: Level C minimum for handling; SCBA and full protective clothing if fire involved or decomposition occurring
ISOLATION: ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill isolate 800m and evacuate downwind
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 1451 — Caesium nitrate
Class: 5 | Placard: Oxidizer | ERG Guide: 140
Appearance: White or colorless crystalline solid, odorless. Hygroscopic powder or crystals at room temperature.
Water Reactivity: Soluble in water without hazardous reaction, but solution may be corrosive
Extinguishing: Water spray, dry chemical, CO2; avoid organic materials and combustibles near oxidizer
PPE: Level C minimum for handling; SCBA and full protective clothing if fire involved or decomposition occurring
Isolation: ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill isolate 800m and evacuate downwind
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• Some may decompose explosively when heated or involved in a fire.
• May explode from heat or contamination.
— 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/1451 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1451 Caesium nitrate Cls5 ERG140 | ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill i | allfirefighter.com/hazmat/un/1451SMS / 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/1451
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Frequently Asked Questions about UN 1451
These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. 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. Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or
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 C minimum for handling; SCBA and full protective clothing if fire involved or decomposition occurring
Water reactivity: Soluble in water without hazardous reaction, but solution may be corrosive. Recommended extinguishing: Water spray, dry chemical, CO2; avoid organic materials and combustibles near oxidizer.
ERG Guide 140 recommendation: ERG 140: isolate spill/leak area 25m in all directions; if fire or large spill isolate 800m and evacuate downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 140 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.