☣️ UN 1951 • CLASS 2
UN 1951 — Argon, refrigerated liquid (cryogenic liquid)
Placard: Non-Flammable Gas. ERG Guide 120. 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.
Advertisement
UN 1951 Quick Details
UN 1951
Product name: Argon, refrigerated liquid (cryogenic liquid)
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 120 (check current ERG)
Initial isolation: ERG 120: isolate spill area 100m all directions; if tank/rail car involved in fire, isolate 800m all directions and consider evacuation
Common Hazards of UN 1951
- Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
| Also known as | Liquid argonLArCryogenic argonRefrigerated argonArgon gas liquefied |
| CAS Number | 7440-37-1 |
| Appearance | Colorless, odorless cryogenic liquid. Boils at extremely low temperature (-186°C). Vapor is colorless and odorless, denser than air when cold. |
| Flash Point | Not applicable (inert gas) |
| Boiling Point | -186°C (-303°F) |
| Vapor Density | 1.38 (heavier than air when cold) |
| Water Reactivity | No reaction - inert gas, but cryogenic temperature can cause violent boiling of water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1951
Extinguishing Media
Not applicable - inert gas, use any agent for surrounding fire
PPE Requirements
⚠️ Cryogenic gloves and face shield for liquid contact; SCBA for confined spaces due to asphyxiation risk; insulated clothing for prolonged exposure
Isolation & Evacuation
ERG 120: isolate spill area 100m all directions; if tank/rail car involved in fire, isolate 800m all directions and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 120).
First Actions for a UN 1951 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 100 meters (330 feet).
Advertisement
📋 Copy & Share Field Card
UN 1951 — Argon, refrigerated liquid (cryogenic liHAZMAT RADIO NOTE — UN 1951
Product: Argon, refrigerated liquid (cryogenic liquid)
Class 2 / Non-Flammable Gas / ERG 120
PPE: Cryogenic gloves and face shield for liquid contact; SCBA for confined spaces due to asphyxiation risk; insulated clothing for prolonged exposure
ISOLATION: ERG 120: isolate spill area 100m all directions; if tank/rail car involved in fire, isolate 800m all directions 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 1951 — Argon, refrigerated liquid (cryogenic liquid)
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 120
Appearance: Colorless, odorless cryogenic liquid. Boils at extremely low temperature (-186°C). Vapor is colorless and odorless, denser than air when cold.
Water Reactivity: No reaction - inert gas, but cryogenic temperature can cause violent boiling of water
Extinguishing: Not applicable - inert gas, use any agent for surrounding fire
PPE: Cryogenic gloves and face shield for liquid contact; SCBA for confined spaces due to asphyxiation risk; insulated clothing for prolonged exposure
Isolation: ERG 120: isolate spill area 100m all directions; if tank/rail car involved in fire, isolate 800m all directions and consider evacuation
— Key Hazards —
• Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
• Vapors from liquefied gas are initially heavier than air and spread along ground.
• Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
— 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/1951 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1951 Argon, refrigerated liquid (cryogenic liquid) Cls2 ERG120 | allfirefighter.com/hazmat/un/1951SMS / 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/1951
Advertisement
Frequently Asked Questions about UN 1951
Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Non-flammable gases. Containers may explode when heated. Ruptured cylinders may rocket.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Cryogenic gloves and face shield for liquid contact; SCBA for confined spaces due to asphyxiation risk; insulated clothing for prolonged exposure
Water reactivity: No reaction - inert gas, but cryogenic temperature can cause violent boiling of water. Recommended extinguishing: Not applicable - inert gas, use any agent for surrounding fire.
ERG Guide 120 recommendation: ERG 120: isolate spill area 100m all directions; if tank/rail car involved in fire, isolate 800m all directions and consider evacuation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 120 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.