UN 1956 — Compressed gas, n.o.s.
Placard: Non-Flammable Gas. ERG Guide 126. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1956 is Compressed gas, n.o.s., a compressed gas n.o.s. entry assigned to ERG Guide 126. The exact gas identity controls asphyxiation, toxicity, frostbite and fire risk.
Hazard overview: UN 1956 presents pressure, cylinder rupture, oxygen-displacement and composition-dependent gas hazards.
Response guidance: For a UN 1956 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 126. Establish incident command, isolate the area, stay upwind, control ignition or downwind hazards, cool exposed containers from a protected distance when appropriate and base entry decisions on monitoring and local SOP.
Firefighter training notes: Training for UN 1956 should emphasize pressure hazards, oxygen displacement, frostbite, cylinder rupture/rocket risk, ventilation and atmospheric monitoring. Use ERG 126, SDS and local SOP.
Regulatory context: Compressed gas, n.o.s. is regulated as a hazardous material for transportation and emergency response purposes. Requirements for storage, workplace exposure, emergency planning, spill reporting and waste handling vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Compressed gas, n.o.s. should be stored in compatible containers in a secure, cool, ventilated hazardous-material area according to SDS and local procedures.
UN 1956 Quick Details
Common Hazards of UN 1956
- COMPRESSED GAS n.o.s.; pressure, cylinder rupture and oxygen-displacement hazards are primary concerns.
- Containers may rupture or rocket when heated.
- Gas may collect in low or confined areas depending on density and composition.
- Contact with liquefied gas may cause frostbite or cold burns.
- Some mixtures may burn or produce toxic decomposition gases even when not readily ignitable.
- Exact hazards depend on the gas identity, pressure, concentration and SDS.
Chemical Identity & Physical Properties
Colorless to variable color gas depending on composition. Odorless or variable odor. Exists as compressed gas at room temperature under pressure in cylinders or containers.
| Also known as | Compressed gas not otherwise specifiedCompressed gas NOSNon-flammable compressed gas mixturePressurized gas mixture |
| Appearance | Colorless to variable color gas depending on composition. Odorless or variable odor. Exists as compressed gas at room temperature under pressure in cylinders or containers. |
| Flash Point | Not applicable (compressed gas, non-flammable) |
| Boiling Point | Variable depending on specific gas composition |
| Vapor Density | Variable depending on specific gas; may be heavier or lighter than air |
| Water Reactivity | Generally no significant reaction with water, though composition-dependent |
Fireground Response Guidance — UN 1956
Extinguishing Media
PPE Requirements
Use SCBA and oxygen monitoring in confined or oxygen-deficient areas. Wear face shield, insulated or cryogenic gloves and protective clothing when liquefied or refrigerated gas contact is possible.
Isolation & Evacuation
First Actions for a UN 1956 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing gas, vapor, smoke or mist and avoid skin or eye contact.
- Do not touch damaged containers or spilled/released material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the release area and expand the perimeter for fire involvement, cylinder heating, vapor accumulation, unknown gas identity or downwind exposure.
- Use ERG Guide 126, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1956 — Compressed gas, 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.