UN 3158 — Gas, refrigerated liquid, n.o.s.
Placard: Non-Flammable Gas. ERG Guide 120. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3158 is Gas, refrigerated liquid, n.o.s., a refrigerated liquefied gas entry assigned to ERG Guide 120. Cryogenic burns and oxygen displacement are major hazards.
Hazard overview: Refrigerated liquefied gas, n.o.s.; extreme cold can cause severe frostbite and brittle fracture of materials. Rapid vaporization can displace oxygen and cause asphyxiation without warning. Cold vapor clouds can initially stay low and move along the ground.
Response guidance: For UN 3158, isolate the area, avoid exposure and use SCBA where vapor, gas, dust, smoke or fire is present. Verify exact contents with SDS, labels and ERG 120.
Firefighter training notes: Training for UN 3158 should emphasize cylinder/package recognition, vapor density, air monitoring, SCBA use, frostbite/toxicity controls, isolation and source-control limits. Use ERG 120, SDS and local SOP.
Regulatory context: Gas, refrigerated liquid, 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: Gas, refrigerated liquid, 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 3158 Quick Details
Common Hazards of UN 3158
- Refrigerated liquefied gas, n.o.s.; extreme cold can cause severe frostbite and brittle fracture of materials.
- Rapid vaporization can displace oxygen and cause asphyxiation without warning.
- Cold vapor clouds can initially stay low and move along the ground.
- Specific gas may be inert, oxidizing, toxic or flammable; do not assume exact behavior without shipping papers.
- Containers exposed to fire may vent, rupture or rocket.
- Water contact may cause rapid boiling and vapor cloud expansion.
- Ventilation and oxygen monitoring are critical in low or confined spaces.
Chemical Identity & Physical Properties
Colorless to pale liquid when refrigerated, boiling and producing vapors at ambient temperature. Odor varies by specific gas. Extremely cold (-150°C to -200°C range) cryogenic liquid.
| Also known as | Refrigerated liquefied gas n.o.s.Cryogenic liquid gas n.o.s.LNG (generic)Liquefied cryogenic gas |
| Appearance | Colorless to pale liquid when refrigerated, boiling and producing vapors at ambient temperature. Odor varies by specific gas. Extremely cold (-150°C to -200°C range) cryogenic liquid. |
| Flash Point | Not applicable (varies by specific gas composition) |
| Boiling Point | Varies by gas (-150°C to -200°C typical range for cryogenic liquids) |
| Vapor Density | Initially heavier than air when released, spreads along ground |
| Water Reactivity | No significant reaction with water, but rapid vaporization may occur |
Fireground Response Guidance — UN 3158
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 3158 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.
- 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 120, SDS, shipping papers, markings and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3158 — Gas, refrigerated liquid, 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.