☣️ UN 1001 • CLASS 2
UN 1001 — Acetylene, dissolved
Placard: Flammable Gas. ERG Guide 116. 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 1001 Quick Details
UN 1001
Product name: Acetylene, dissolved
DOT Class: 2
Placard type: Flammable Gas
ERG Guide: 116 (check current ERG)
Initial isolation: ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if tank/rail car involved in fire
Common Hazards of UN 1001
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the
- Disilane (UN3553) and Silane (UN2203) will ignite spontaneously in air and may re-ignite.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
Chemical Identity & Physical Properties
| Also known as | EthyneNarcylenVinyleneEthine |
| CAS Number | 74-86-2 |
| Appearance | Colorless gas with a faint ethereal odor when pure, garlic-like odor when impure. Lighter than air, shipped dissolved in acetone under pressure in cylinders. |
| Flash Point | Not applicable (gas) |
| Boiling Point | -84C (-119F) |
| Vapor Density | 0.9 (lighter than air) |
| Water Reactivity | No significant reaction with water; slightly soluble |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1001
Extinguishing Media
CO2, dry chemical, water spray for cooling cylinders; no foam needed for gas
PPE Requirements
⚠️ Level B minimum; SCBA required; fire-entry suits for fire involvement; avoid all ignition sources
Isolation & Evacuation
ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if tank/rail car involved in fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 116).
First Actions for a UN 1001 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
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 800 meters (1/2 mile).
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📋 Copy & Share Field Card
UN 1001 — Acetylene, dissolvedHAZMAT RADIO NOTE — UN 1001
Product: Acetylene, dissolved
Class 2 / Flammable Gas / ERG 116
PPE: Level B minimum; SCBA required; fire-entry suits for fire involvement; avoid all ignition sources
ISOLATION: ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if tank/rail car involved in fire
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 1001 — Acetylene, dissolved
Class: 2 | Placard: Flammable Gas | ERG Guide: 116
Appearance: Colorless gas with a faint ethereal odor when pure, garlic-like odor when impure. Lighter than air, shipped dissolved in acetone under pressure in cylinders.
Water Reactivity: No significant reaction with water; slightly soluble
Extinguishing: CO2, dry chemical, water spray for cooling cylinders; no foam needed for gas
PPE: Level B minimum; SCBA required; fire-entry suits for fire involvement; avoid all ignition sources
Isolation: ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if tank/rail car involved in fire
— Key Hazards —
• EXTREMELY FLAMMABLE.
• Will be easily ignited by heat, sparks or flames.
• Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the
— 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/1001 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1001 Acetylene, dissolved Cls2 ERG116 | ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if | allfirefighter.com/hazmat/un/1001SMS / 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/1001
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Frequently Asked Questions about UN 1001
EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the Disilane (UN3553) and Silane (UN2203) will ignite spontaneously in air and may re-ignite. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
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; SCBA required; fire-entry suits for fire involvement; avoid all ignition sources
Water reactivity: No significant reaction with water; slightly soluble. Recommended extinguishing: CO2, dry chemical, water spray for cooling cylinders; no foam needed for gas.
ERG Guide 116 recommendation: ERG 116: isolate 800m all directions for large spill; evacuate 1600m downwind if tank/rail car involved in fire
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 116 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.