☣️ UN 1956 • CLASS 2

Compressed gas, n.o.s.

Placard: Non-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 1956
Class: 2
Placard type: Non-Flammable Gas
ERG: Guide 126 (check current ERG)
Verify shipping papers and exact product details; use ERG Guide 126 for initial actions and isolation/evacuation guidance.
Common hazards (high level)
  • Some may burn but none ignite readily.
  • Containers may explode when heated.
  • Ruptured cylinders may rocket.
  • Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
  • Vapors from liquefied gas are initially heavier than air and spread along ground.
  • Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
  • Fire may produce irritating, corrosive and/or toxic gases.
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
  • Ventilate closed spaces before entering, but only if properly trained and equipped.
  • Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
  • Consider initial downwind evacuation for at least 500 meters (1/3 mile).
Related UN numbers (same class)
This is a discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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MAYDAY / HAZMAT QUICK NOTE
UN 1956 — Compressed gas, n.o.s.
Class: 2 | Placard: Non-Flammable Gas
ERG: Guide 126 (check current ERG)
FIRST ACTIONS: use SOP/SOG + ERG; stage upwind; isolate; deny entry; request Hazmat.
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FAQ

Some may burn but none ignite readily. Containers may explode when heated. Ruptured cylinders may rocket. Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating, corrosive and/or toxic gases.

CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.

Full protective clothing minimum. Consult ERG Guide 126 and your SOP/SOG for specific PPE requirements.

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 126 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.