☣️ UN 1956 • CLASS 2
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.
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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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UN 1956 Quick Details
UN 1956
Product name: Compressed gas, n.o.s.
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 126 (check current ERG)
Initial isolation: ERG 126: Initial isolation 100m in all directions; protect persons downwind; evacuate immediate area if cylinder rupture or fire involved
Common Hazards of UN 1956
- 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.
Chemical Identity & Physical Properties
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1956
Extinguishing Media
Not applicable for gases; use appropriate gas control methods, ventilation
PPE Requirements
⚠️ Level B minimum recommended; SCBA required in confined spaces or unknown atmospheres; chemical-resistant gloves and suit
Isolation & Evacuation
ERG 126: Initial isolation 100m in all directions; protect persons downwind; evacuate immediate area if cylinder rupture or fire involved
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 126).
First Actions for a UN 1956 Incident
- 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).
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UN 1956 — Compressed gas, n.o.s.HAZMAT RADIO NOTE — UN 1956
Product: Compressed gas, n.o.s.
Class 2 / Non-Flammable Gas / ERG 126
PPE: Level B minimum recommended; SCBA required in confined spaces or unknown atmospheres; chemical-resistant gloves and suit
ISOLATION: ERG 126: Initial isolation 100m in all directions; protect persons downwind; evacuate immediate area if cylinder rupture or fire involved
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 1956 — Compressed gas, n.o.s.
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 126
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.
Water Reactivity: Generally no significant reaction with water, though composition-dependent
Extinguishing: Not applicable for gases; use appropriate gas control methods, ventilation
PPE: Level B minimum recommended; SCBA required in confined spaces or unknown atmospheres; chemical-resistant gloves and suit
Isolation: ERG 126: Initial isolation 100m in all directions; protect persons downwind; evacuate immediate area if cylinder rupture or fire involved
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Ruptured cylinders may rocket.
— 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/1956 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1956 Compressed gas, n.o.s. Cls2 ERG126 | ERG 126: Initial isolation 100m in all directions; protect persons downwind; eva | allfirefighter.com/hazmat/un/1956SMS / 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/1956
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Frequently Asked Questions about UN 1956
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.
Level B minimum recommended; SCBA required in confined spaces or unknown atmospheres; chemical-resistant gloves and suit
Water reactivity: Generally no significant reaction with water, though composition-dependent. Recommended extinguishing: Not applicable for gases; use appropriate gas control methods, ventilation.
ERG Guide 126 recommendation: ERG 126: Initial isolation 100m in all directions; protect persons downwind; evacuate immediate area if cylinder rupture or fire involved
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.