☣️ UN 3311 • CLASS 2
Gas, refrigerated liquid, oxidizing, n.o.s.
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 3311
Class: 2
Placard type: Non-Flammable Gas
ERG: Guide 122 (check current ERG)
Isolation: ERG 122: isolate 800m (1/2 mile) all directions initially; evacuate 1600m (1 mile) downwind if tank is involved in fire
Chemical & Response Details
| Also known as | Cryogenic oxidizing gasRefrigerated liquefied oxidizing gasCryogenic liquid oxidizerLiquefied oxidizing gas |
| Appearance | Cryogenic liquid maintained at very low temperatures (typically below -150°C). Color and odor vary depending on specific gas; typically colorless to pale colored liquid that rapidly boils and evaporates at ambient temperature producing dense white vapor clouds. |
| Flash Point | Not applicable (non-flammable oxidizing gas) |
| Boiling Point | Varies by specific gas, typically -150°C to -183°C (-238°F to -297°F) |
| Vapor Density | Varies by gas; most oxidizing gases are heavier than air when cold |
| Water Reactivity | No significant reaction with water, but extreme cold can cause violent boiling and splashing |
| Extinguishing | Do not use water or foam; use dry chemical or CO2 for small fires; flood area with water from safe distance for large fires |
| PPE | ⚠️ Level A or B with SCBA required; insulated cryogenic gloves and face shield mandatory; avoid contact with liquid (severe frostbite hazard) |
| Isolation | ERG 122: isolate 800m (1/2 mile) all directions initially; evacuate 1600m (1 mile) downwind if tank is involved in 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 3311 — Gas, refrigerated liquid, oxidizing, n.o HAZMAT RADIO NOTE — UN 3311
Product: Gas, refrigerated liquid, oxidizing, n.o.s.
Class 2 / Non-Flammable Gas / ERG 122
PPE: Level A or B with SCBA required; insulated cryogenic gloves and face shield mandatory; avoid contact with liquid (severe frostbite hazard)
ISOLATION: ERG 122: isolate 800m (1/2 mile) all directions initially; evacuate 1600m (1 mile) downwind if tank is involved in 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 3311 — Gas, refrigerated liquid, oxidizing, n.o.s.
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 122
Appearance: Cryogenic liquid maintained at very low temperatures (typically below -150°C). Color and odor vary depending on specific gas; typically colorless to pale colored liquid that rapidly boils and evaporates at ambient temperature producing dense white vapor clouds.
Water Reactivity: No significant reaction with water, but extreme cold can cause violent boiling and splashing
Extinguishing: Do not use water or foam; use dry chemical or CO2 for small fires; flood area with water from safe distance for large fires
PPE: Level A or B with SCBA required; insulated cryogenic gloves and face shield mandatory; avoid contact with liquid (severe frostbite hazard)
Isolation: ERG 122: isolate 800m (1/2 mile) all directions initially; evacuate 1600m (1 mile) downwind if tank is involved in 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/3311 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3311 Gas, refrigerated liquid, oxidizing, n.o.s. Cls2 ERG122 | allfirefighter.com/hazmat/un/3311SMS / 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/3311
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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 A or B with SCBA required; insulated cryogenic gloves and face shield mandatory; avoid contact with liquid (severe frostbite hazard)
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.