☣️ UN 1046 • CLASS 2
UN 1046 — Helium, compressed
Placard: Non-Flammable Gas. ERG Guide 120. 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 1046 Quick Details
UN 1046
Product name: Helium, compressed
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 120 (check current ERG)
Initial isolation: ERG 121: Initial isolation 100m all directions; no evacuation distances for small spills; ventilate confined spaces to prevent asphyxiation
Common Hazards of UN 1046
- 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, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
| Also known as | Helium gasHeHelium-4Compressed heliumLiquid helium |
| CAS Number | 7440-59-7 |
| Appearance | Colorless, odorless, tasteless inert gas at room temperature. Colorless liquid at cryogenic temperatures (-269°C). Lightest noble gas. |
| Flash Point | Not applicable (inert gas) |
| Boiling Point | -269°C (-452°F) |
| Vapor Density | 0.14 (lighter than air) |
| Water Reactivity | No reaction, inert gas |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1046
Extinguishing Media
Not applicable (inert gas); no extinguishing agents needed
PPE Requirements
⚠️ Level D for gas release; Level A with SCBA for confined spaces or oxygen-deficient atmospheres; insulated gloves for cryogenic liquid contact
Isolation & Evacuation
ERG 121: Initial isolation 100m all directions; no evacuation distances for small spills; ventilate confined spaces to prevent asphyxiation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 120).
First Actions for a UN 1046 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 100 meters (330 feet).
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📋 Copy & Share Field Card
UN 1046 — Helium, compressedHAZMAT RADIO NOTE — UN 1046
Product: Helium, compressed
Class 2 / Non-Flammable Gas / ERG 120
PPE: Level D for gas release; Level A with SCBA for confined spaces or oxygen-deficient atmospheres; insulated gloves for cryogenic liquid contact
ISOLATION: ERG 121: Initial isolation 100m all directions; no evacuation distances for small spills; ventilate confined spaces to prevent asphyxiation
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 1046 — Helium, compressed
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 120
Appearance: Colorless, odorless, tasteless inert gas at room temperature. Colorless liquid at cryogenic temperatures (-269°C). Lightest noble gas.
Water Reactivity: No reaction, inert gas
Extinguishing: Not applicable (inert gas); no extinguishing agents needed
PPE: Level D for gas release; Level A with SCBA for confined spaces or oxygen-deficient atmospheres; insulated gloves for cryogenic liquid contact
Isolation: ERG 121: Initial isolation 100m all directions; no evacuation distances for small spills; ventilate confined spaces to prevent asphyxiation
— Key Hazards —
• 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, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
— 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/1046 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1046 Helium, compressed Cls2 ERG120 | ERG 121: Initial isolation 100m all directions; no evacuation distances for smal | allfirefighter.com/hazmat/un/1046SMS / 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/1046
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Frequently Asked Questions about UN 1046
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, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Non-flammable gases. Containers may explode when heated. Ruptured cylinders may rocket.
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 D for gas release; Level A with SCBA for confined spaces or oxygen-deficient atmospheres; insulated gloves for cryogenic liquid contact
Water reactivity: No reaction, inert gas. Recommended extinguishing: Not applicable (inert gas); no extinguishing agents needed.
ERG Guide 120 recommendation: ERG 121: Initial isolation 100m all directions; no evacuation distances for small spills; ventilate confined spaces to prevent asphyxiation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 120 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.