☣️ UN 2591 • CLASS 2
UN 2591 — Xenon, refrigerated liquid (cryogenic liquid)
Placard: Non-Flammable Gas. ERG Guide 120. 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 2591 Quick Details
UN 2591
Product name: Xenon, refrigerated liquid (cryogenic liquid)
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 120 (check current ERG)
Initial isolation: ERG 120: Isolate 100m in all directions initially; evacuate immediate area if large spill; ensure adequate ventilation in confined spaces
Common Hazards of UN 2591
- 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 | XenonLiquid xenonCryogenic xenonLXeRefrigerated liquid xenon |
| CAS Number | 7440-63-3 |
| Appearance | Colorless, odorless cryogenic liquid or compressed gas. Boiling point is extremely low at -108°C (-162°F), creating dense white vapors upon release. |
| Flash Point | Not applicable (inert gas) |
| Boiling Point | -108C (-162F) |
| Vapor Density | 4.5 (heavier than air) |
| Water Reactivity | No reaction, inert noble gas |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2591
Extinguishing Media
Not applicable - use ventilation, no combustion hazard
PPE Requirements
⚠️ Insulated cryogenic gloves and face shield for liquid contact; SCBA in confined spaces due to asphyxiation risk
Isolation & Evacuation
ERG 120: Isolate 100m in all directions initially; evacuate immediate area if large spill; ensure adequate ventilation in confined spaces
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 120).
First Actions for a UN 2591 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).
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📋 Copy & Share Field Card
UN 2591 — Xenon, refrigerated liquid (cryogenic liHAZMAT RADIO NOTE — UN 2591
Product: Xenon, refrigerated liquid (cryogenic liquid)
Class 2 / Non-Flammable Gas / ERG 120
PPE: Insulated cryogenic gloves and face shield for liquid contact; SCBA in confined spaces due to asphyxiation risk
ISOLATION: ERG 120: Isolate 100m in all directions initially; evacuate immediate area if large spill; ensure adequate ventilation in confined spaces
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 2591 — Xenon, refrigerated liquid (cryogenic liquid)
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 120
Appearance: Colorless, odorless cryogenic liquid or compressed gas. Boiling point is extremely low at -108°C (-162°F), creating dense white vapors upon release.
Water Reactivity: No reaction, inert noble gas
Extinguishing: Not applicable - use ventilation, no combustion hazard
PPE: Insulated cryogenic gloves and face shield for liquid contact; SCBA in confined spaces due to asphyxiation risk
Isolation: ERG 120: Isolate 100m in all directions initially; evacuate immediate area if large spill; ensure adequate ventilation in confined spaces
— 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/2591 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2591 Xenon, refrigerated liquid (cryogenic liquid) Cls2 ERG120 | allfirefighter.com/hazmat/un/2591SMS / 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/2591
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Frequently Asked Questions about UN 2591
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.
Insulated cryogenic gloves and face shield for liquid contact; SCBA in confined spaces due to asphyxiation risk
Water reactivity: No reaction, inert noble gas. Recommended extinguishing: Not applicable - use ventilation, no combustion hazard.
ERG Guide 120 recommendation: ERG 120: Isolate 100m in all directions initially; evacuate immediate area if large spill; ensure adequate ventilation in confined spaces
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.