☣️ UN 2451 • CLASS 2
UN 2451 — Nitrogen trifluoride
Placard: Non-Flammable Gas. ERG Guide 122. 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 2451 Quick Details
UN 2451
Product name: Nitrogen trifluoride
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 122 (check current ERG)
Initial isolation: ERG 122: isolate 100m all directions initially; if tank/rail car involved in fire isolate 800m and evacuate 1600m downwind
Common Hazards of UN 2451
- Substance does not burn but will support combustion.
- Some may react explosively with fuels.
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Runoff may create fire or explosion hazard.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
- Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
Chemical Identity & Physical Properties
| Also known as | NF3Nitrogen fluorideTrifluoroaminePerfluoroammonia |
| CAS Number | 7783-54-2 |
| Appearance | Colorless, odorless compressed gas. Non-flammable but acts as a strong oxidizer. Shipped as a liquefied compressed gas under high pressure. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -129C (-200F) |
| Vapor Density | 2.5 (heavier than air) |
| Water Reactivity | Reacts slowly with water producing toxic and corrosive hydrogen fluoride gas |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2451
Extinguishing Media
Do not use water or foam; use dry chemical or CO2 extinguishers only
PPE Requirements
⚠️ Level A for spills/leaks; SCBA required; chemical-resistant suit; avoid contact with oxidizable materials
Isolation & Evacuation
ERG 122: isolate 100m all directions initially; if tank/rail car involved in fire isolate 800m and evacuate 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 122).
First Actions for a UN 2451 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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 500 meters (1/3 mile).
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📋 Copy & Share Field Card
UN 2451 — Nitrogen trifluorideHAZMAT RADIO NOTE — UN 2451
Product: Nitrogen trifluoride
Class 2 / Non-Flammable Gas / ERG 122
PPE: Level A for spills/leaks; SCBA required; chemical-resistant suit; avoid contact with oxidizable materials
ISOLATION: ERG 122: isolate 100m all directions initially; if tank/rail car involved in fire isolate 800m and evacuate 1600m 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 2451 — Nitrogen trifluoride
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 122
Appearance: Colorless, odorless compressed gas. Non-flammable but acts as a strong oxidizer. Shipped as a liquefied compressed gas under high pressure.
Water Reactivity: Reacts slowly with water producing toxic and corrosive hydrogen fluoride gas
Extinguishing: Do not use water or foam; use dry chemical or CO2 extinguishers only
PPE: Level A for spills/leaks; SCBA required; chemical-resistant suit; avoid contact with oxidizable materials
Isolation: ERG 122: isolate 100m all directions initially; if tank/rail car involved in fire isolate 800m and evacuate 1600m downwind
— Key Hazards —
• Substance does not burn but will support combustion.
• Some may react explosively with fuels.
• May ignite combustibles (wood, paper, oil, clothing, etc.).
— 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.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/2451 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2451 Nitrogen trifluoride Cls2 ERG122 | ERG 122: isolate 100m all directions initially; if tank/rail car involved in fir | allfirefighter.com/hazmat/un/2451SMS / 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/2451
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Frequently Asked Questions about UN 2451
Substance does not burn but will support combustion. Some may react explosively with fuels. May ignite combustibles (wood, paper, oil, clothing, etc.). Vapors from liquefied gas are initially heavier than air and spread along ground. Runoff may create fire or explosion hazard. Containers may explode when heated. Ruptured cylinders may rocket. Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
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 for spills/leaks; SCBA required; chemical-resistant suit; avoid contact with oxidizable materials
Water reactivity: Reacts slowly with water producing toxic and corrosive hydrogen fluoride gas. Recommended extinguishing: Do not use water or foam; use dry chemical or CO2 extinguishers only.
ERG Guide 122 recommendation: ERG 122: isolate 100m all directions initially; if tank/rail car involved in fire isolate 800m and evacuate 1600m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 122 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.