☣️ UN 3312 • CLASS 2
UN 3312 — Gas, refrigerated liquid, flammable, n.o.s.
Placard: Flammable Gas. ERG Guide 115. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
UN 3312 covers refrigerated liquid flammable gases. A release can rapidly vaporize into a flammable vapor cloud while also creating cryogenic burn hazards.
Hazard overview: The gas is extremely flammable and can form explosive mixtures with air. Vapors may travel to ignition sources and flash back, while contact with the refrigerated liquid can cause frostbite.
Response guidance: Eliminate ignition sources, isolate the area, and do not extinguish a burning gas release unless the leak can be stopped. Use water spray only for cooling exposed containers from a safe distance.
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UN 3312 Quick Details
UN 3312
Product name: Gas, refrigerated liquid, flammable, n.o.s.
DOT Class: 2
Placard type: Flammable Gas
ERG Guide: 115 (check current ERG)
Initial isolation: ERG 115: Initial isolation 200m all directions; Protective Action Distance: Large spill daytime 800m, nighttime 2000m
Common Hazards of UN 3312
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
Colorless to light-colored cryogenic liquid stored at extremely low temperatures (typically below -100°C). Odor varies depending on specific gas; rapidly vaporizes when released, forming dense vapor clouds.
| Also known as | Cryogenic flammable gasLiquefied flammable gas (refrigerated)Refrigerated liquefied flammable gas n.o.s.Cryogenic liquid flammable gas |
| Appearance | Colorless to light-colored cryogenic liquid stored at extremely low temperatures (typically below -100°C). Odor varies depending on specific gas; rapidly vaporizes when released, forming dense vapor clouds. |
| Flash Point | Not applicable (cryogenic liquid/gas) |
| Boiling Point | Varies by specific gas (typically -100°C to -200°C or lower) |
| Vapor Density | Varies by specific gas (may be lighter or heavier than air) |
| Water Reactivity | No significant reaction with water, but contact may cause violent boiling and rapid vaporization |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3312
Extinguishing Media
CO2, dry chemical, water spray for cooling only; do not direct water at liquid
PPE Requirements
⚠️ Level B minimum; SCBA required; insulated gloves for cryogenic exposure; full face shield; avoid all skin contact with cryogenic liquid
Level B minimum; SCBA required; insulated gloves for cryogenic exposure; full face shield; avoid all skin contact with cryogenic liquid
Isolation & Evacuation
ERG 115: Initial isolation 200m all directions; Protective Action Distance: Large spill daytime 800m, nighttime 2000m
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 115).
First Actions for a UN 3312 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 800 meters (1/2 mile).
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📋 Copy & Share Field Card
UN 3312 — Gas, refrigerated liquid, flammable, n.oHAZMAT RADIO NOTE — UN 3312
Product: Gas, refrigerated liquid, flammable, n.o.s.
Class 2 / Flammable Gas / ERG 115
PPE: Level B minimum; SCBA required; insulated gloves for cryogenic exposure; full face shield; avoid all skin contact with cryogenic liquid
ISOLATION: ERG 115: Initial isolation 200m all directions; Protective Action Distance: Large spill daytime 800m, nighttime 2000m
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 3312 — Gas, refrigerated liquid, flammable, n.o.s.
Class: 2 | Placard: Flammable Gas | ERG Guide: 115
Appearance: Colorless to light-colored cryogenic liquid stored at extremely low temperatures (typically below -100°C). Odor varies depending on specific gas; rapidly vaporizes when released, forming dense vapor clouds.
Water Reactivity: No significant reaction with water, but contact may cause violent boiling and rapid vaporization
Extinguishing: CO2, dry chemical, water spray for cooling only; do not direct water at liquid
PPE: Level B minimum; SCBA required; insulated gloves for cryogenic exposure; full face shield; avoid all skin contact with cryogenic liquid
Isolation: ERG 115: Initial isolation 200m all directions; Protective Action Distance: Large spill daytime 800m, nighttime 2000m
— Key Hazards —
• EXTREMELY FLAMMABLE.
• Will be easily ignited by heat, sparks or flames.
• Will form explosive mixtures with air.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
• Consider initial downwind evacuation for at least 800 meters (1/2 mile).
SOURCE: allfirefighter.com/hazmat/un/gas-refrigerated-liquid-flammable-un-3312 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3312 Gas, refrigerated liquid, flammable, n.o.s. Cls2 ERG115 | allfirefighter.com/hazmat/un/gas-refrigerated-liquid-flammable-un-3312SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/gas-refrigerated-liquid-flammable-un-3312
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Frequently Asked Questions about UN 3312
Yes. UN 3312 is an extremely flammable refrigerated liquefied gas.
It can rapidly vaporize and form a flammable vapor cloud that may flash back to the source.
Do not extinguish a burning gas leak unless the flow can be stopped safely.
SCBA, protective clothing, face protection, and insulated gloves are needed for cryogenic exposure.
Use water spray only for cooling containers; do not direct water streams into the liquid release.
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.