☣️ UN 3312 • CLASS 2
Gas, refrigerated liquid, flammable, n.o.s.
Placard: 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 3312
Class: 2
Placard type: Flammable Gas
ERG: Guide 115 (check current ERG)
Isolation: ERG 115: Initial isolation 200m all directions; Protective Action Distance: Large spill daytime 800m, nighttime 2000m
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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
- 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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UN 3312 — Gas, refrigerated liquid, flammable, n.o HAZMAT 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 —
• 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/3312 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3312 Gas, refrigerated liquid, flammable, n.o.s. Cls2 ERG115 | allfirefighter.com/hazmat/un/3312SMS / 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/3312
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FAQ
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.
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; SCBA required; insulated gloves for cryogenic exposure; full face shield; avoid all skin contact with cryogenic liquid
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 115 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.