☣️ UN 1055 • CLASS 2
UN 1055 — Isobutylene
Placard: Flammable Gas. ERG Guide 115. 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 1055 Quick Details
UN 1055
Product name: Isobutylene
DOT Class: 2
Placard type: Flammable Gas
ERG Guide: 115 (check current ERG)
Initial isolation: ERG 115: Initial isolate 100m all directions; protect from ignition sources; evacuate downwind if leaking or on fire
Common Hazards of UN 1055
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air.
- 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.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
| Also known as | 2-MethylpropeneIsobutene2-Methyl-1-propeneLiquefied petroleum gas (LPG component) |
| CAS Number | 115-11-7 |
| Appearance | Colorless gas with a faint petroleum-like odor. Shipped as a liquefied compressed gas under pressure. |
| Flash Point | -76C (-105F) |
| Boiling Point | -7C (20F) |
| Vapor Density | 1.9 (heavier 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 1055
Extinguishing Media
CO2, dry chemical, water spray for cooling containers only; avoid directing water into liquid
PPE Requirements
⚠️ Level B minimum with SCBA and chemical-resistant suit; Cold contact hazard from liquefied gas
Isolation & Evacuation
ERG 115: Initial isolate 100m all directions; protect from ignition sources; evacuate downwind if leaking or on fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 115).
First Actions for a UN 1055 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 1055 — IsobutyleneHAZMAT RADIO NOTE — UN 1055
Product: Isobutylene
Class 2 / Flammable Gas / ERG 115
PPE: Level B minimum with SCBA and chemical-resistant suit; Cold contact hazard from liquefied gas
ISOLATION: ERG 115: Initial isolate 100m all directions; protect from ignition sources; evacuate downwind if leaking or on 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 1055 — Isobutylene
Class: 2 | Placard: Flammable Gas | ERG Guide: 115
Appearance: Colorless gas with a faint petroleum-like odor. Shipped as a liquefied compressed gas under pressure.
Water Reactivity: No significant reaction with water; slightly soluble
Extinguishing: CO2, dry chemical, water spray for cooling containers only; avoid directing water into liquid
PPE: Level B minimum with SCBA and chemical-resistant suit; Cold contact hazard from liquefied gas
Isolation: ERG 115: Initial isolate 100m all directions; protect from ignition sources; evacuate downwind if leaking or on fire
— Key Hazards —
• EXTREMELY FLAMMABLE.
• Will be easily ignited by heat, sparks or flames.
• Will form explosive mixtures with air.
— 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/1055 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1055 Isobutylene Cls2 ERG115 | ERG 115: Initial isolate 100m all directions; protect from ignition sources; eva | allfirefighter.com/hazmat/un/1055SMS / 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/1055
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Frequently Asked Questions about UN 1055
EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. 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. 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 B minimum with SCBA and chemical-resistant suit; Cold contact hazard from liquefied gas
Water reactivity: No significant reaction with water; slightly soluble. Recommended extinguishing: CO2, dry chemical, water spray for cooling containers only; avoid directing water into liquid.
ERG Guide 115 recommendation: ERG 115: Initial isolate 100m all directions; protect from ignition sources; evacuate downwind if leaking or on fire
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 115 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.