☣️ UN 2201 • CLASS 2
Nitrous oxide, refrigerated liquid
Placard: Non-Flammable Gas. 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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Quick details
UN 2201
Class: 2
Placard type: Non-Flammable Gas
ERG: Guide 122 (check current ERG)
Isolation: ERG 122: Initial isolation 100m all directions; Protective action distance 800m downwind for large spill; evacuate area if containers exposed to fire
Chemical & Response Details
| Also known as | Laughing gasDinitrogen monoxideN2ONitrous oxide cryogenic liquidNitrogen oxide (N2O) |
| CAS Number | 10024-97-2 |
| Appearance | Colorless, odorless to slightly sweet-smelling cryogenic liquid that boils at very low temperature. Gas is also colorless with a faint sweet odor. |
| Flash Point | Not applicable (non-flammable oxidizing gas) |
| Boiling Point | -88.5C (-127.3F) |
| Vapor Density | 1.53 (heavier than air) |
| Water Reactivity | No significant reaction with water; dissolves slightly |
| Extinguishing | Not applicable for suppression; use water spray to cool containers, does not burn but supports combustion |
| PPE | ⚠️ Level B minimum for liquid exposure; SCBA required in high concentrations; insulated cryogenic gloves for liquid contact; risk of frostbite and asphyxiation |
| Isolation | ERG 122: Initial isolation 100m all directions; Protective action distance 800m downwind for large spill; evacuate area if containers exposed to fire |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
First actions (field-minded)
- 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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UN 2201 — Nitrous oxide, refrigerated liquid HAZMAT RADIO NOTE — UN 2201
Product: Nitrous oxide, refrigerated liquid
Class 2 / Non-Flammable Gas / ERG 122
PPE: Level B minimum for liquid exposure; SCBA required in high concentrations; insulated cryogenic gloves for liquid contact; risk of frostbite and asphyxiation
ISOLATION: ERG 122: Initial isolation 100m all directions; Protective action distance 800m downwind for large spill; evacuate area if containers exposed to fire
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 2201 — Nitrous oxide, refrigerated liquid
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 122
Appearance: Colorless, odorless to slightly sweet-smelling cryogenic liquid that boils at very low temperature. Gas is also colorless with a faint sweet odor.
Water Reactivity: No significant reaction with water; dissolves slightly
Extinguishing: Not applicable for suppression; use water spray to cool containers, does not burn but supports combustion
PPE: Level B minimum for liquid exposure; SCBA required in high concentrations; insulated cryogenic gloves for liquid contact; risk of frostbite and asphyxiation
Isolation: ERG 122: Initial isolation 100m all directions; Protective action distance 800m downwind for large spill; evacuate area if containers exposed to fire
— 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/2201 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2201 Nitrous oxide, refrigerated liquid Cls2 ERG122 | allfirefighter.com/hazmat/un/2201SMS / 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/2201
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FAQ
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 B minimum for liquid exposure; SCBA required in high concentrations; insulated cryogenic gloves for liquid contact; risk of frostbite and asphyxiation
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.