UN 3161 — Liquefied gas, flammable, n.o.s.
Placard: Flammable Gas. ERG Guide 115. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3161 is Liquefied gas, flammable, n.o.s., a broad flammable liquefied gas entry assigned to ERG Guide 115. Vapor cloud flashback and cylinder rupture are key hazards.
Hazard overview: EXTREMELY FLAMMABLE liquefied gas, n.o.s.; may ignite easily and form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and may travel to ignition sources and flash back. Low areas, drains and confined spaces can collect explosive vapor clouds.
Response guidance: For UN 3161, eliminate ignition sources, isolate low areas and cool cylinders from protection. Do not extinguish a leaking gas fire unless flow can be stopped safely.
Firefighter training notes: Training for UN 3161 should emphasize cylinder/package recognition, vapor density, air monitoring, SCBA use, frostbite/toxicity controls, isolation and source-control limits. Use ERG 115, SDS and local SOP.
Regulatory context: Liquefied gas, flammable, n.o.s. is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, package type, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Liquefied gas, flammable, n.o.s. should be stored in secured, compatible cylinders or sample packages away from heat, physical damage and unauthorized access, with ventilation, segregation and emergency planning based on exact gas identity.
UN 3161 Quick Details
Common Hazards of UN 3161
- EXTREMELY FLAMMABLE liquefied gas, n.o.s.; may ignite easily and form explosive mixtures with air.
- Vapors from liquefied gas are initially heavier than air and may travel to ignition sources and flash back.
- Low areas, drains and confined spaces can collect explosive vapor clouds.
- Liquefied gas contact can cause frostbite or cold burns.
- Cylinders exposed to fire may vent, rupture or rocket.
- Fire may produce toxic or irritating decomposition products depending on gas composition.
- Exact gas blend must be verified from cylinder markings, SDS and shipping papers.
Chemical Identity & Physical Properties
Colorless to pale yellow liquefied gas under pressure with characteristic odor depending on specific gas composition. Rapidly evaporates to gas at room temperature when released.
| Also known as | Liquefied flammable gasCompressed flammable gas liquefiedLPG (various types)Flammable liquefied petroleum gas |
| Appearance | Colorless to pale yellow liquefied gas under pressure with characteristic odor depending on specific gas composition. Rapidly evaporates to gas at room temperature when released. |
| Flash Point | Not applicable (liquefied flammable gas) |
| Boiling Point | Varies by composition, typically -50C to 0C (-58F to 32F) |
| Vapor Density | Heavier than air (typically 1.5-2.0) |
| Water Reactivity | No significant reaction with water |
Fireground Response Guidance — UN 3161
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for releases, fire or confined spaces. Wear eye/face protection and insulated gloves where liquefied or cryogenic gas contact is possible.
Isolation & Evacuation
First Actions for a UN 3161 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, gas, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers, cylinders, articles or spilled material without proper training and PPE.
- Prevent contaminated runoff, debris and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 115, SDS, shipping papers, markings and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3161 — Liquefied gas, flammable, n.o.s.Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.