☣️ UN 2371 • CLASS 3
UN 2371 — Isopentenes
Placard: Flammable. ERG Guide 128. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 2371 Quick Details
UN 2371
Product name: Isopentenes
DOT Class: 3
Placard type: Flammable
ERG Guide: 128 (check current ERG)
Initial isolation: ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m and evacuate downwind 800m. Highly flammable vapors will accumulate in low areas.
Common Hazards of UN 2371
- HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
- Vapors may form explosive mixtures with air.
- Vapors may travel to source of ignition and flash back.
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapor explosion hazard indoors, outdoors or in sewers.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Runoff to sewer may create fire or explosion hazard.
- Containers may explode when heated.
Chemical Identity & Physical Properties
| Also known as | 2-Methyl-2-butene2-Methylbutene-2Trimethylethylenebeta-IsoamyleneIsopentylene |
| CAS Number | 513-35-9 |
| Appearance | Colorless liquid with a disagreeable odor. Exists as a mixture of isomeric unsaturated hydrocarbons (primarily 2-methyl-2-butene and 2-methyl-1-butene). Highly volatile at room temperature. |
| Flash Point | -51C (-60F) |
| Boiling Point | 20-38C (68-100F) depending on isomer |
| Vapor Density | 2.4 (heavier than air) |
| Water Reactivity | Insoluble in water, floats on surface. No significant reaction with water. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2371
Extinguishing Media
AFFF, alcohol-resistant foam, CO2, dry chemical, water spray for cooling
PPE Requirements
⚠️ Level B minimum with SCBA required in vapor areas. Full chemical-resistant suit if liquid contact possible. Extreme explosion hazard requires remote operation.
Isolation & Evacuation
ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m and evacuate downwind 800m. Highly flammable vapors will accumulate in low areas.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 128).
First Actions for a UN 2371 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.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 50 meters (150 feet) in all directions.
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 2371 — IsopentenesHAZMAT RADIO NOTE — UN 2371
Product: Isopentenes
Class 3 / Flammable / ERG 128
PPE: Level B minimum with SCBA required in vapor areas. Full chemical-resistant suit if liquid contact possible. Extreme explosion hazard requires remote operation.
ISOLATION: ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m and evacuate downwind 800m. Highly flammable vapors will accumulate in low areas.
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 2371 — Isopentenes
Class: 3 | Placard: Flammable | ERG Guide: 128
Appearance: Colorless liquid with a disagreeable odor. Exists as a mixture of isomeric unsaturated hydrocarbons (primarily 2-methyl-2-butene and 2-methyl-1-butene). Highly volatile at room temperature.
Water Reactivity: Insoluble in water, floats on surface. No significant reaction with water.
Extinguishing: AFFF, alcohol-resistant foam, CO2, dry chemical, water spray for cooling
PPE: Level B minimum with SCBA required in vapor areas. Full chemical-resistant suit if liquid contact possible. Extreme explosion hazard requires remote operation.
Isolation: ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m and evacuate downwind 800m. Highly flammable vapors will accumulate in low areas.
— Key Hazards —
• HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
• Vapors may form explosive mixtures with air.
• Vapors may travel to source of ignition and flash back.
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/2371 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2371 Isopentenes Cls3 ERG128 | ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m | allfirefighter.com/hazmat/un/2371SMS / 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/2371
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Frequently Asked Questions about UN 2371
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated.
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 required in vapor areas. Full chemical-resistant suit if liquid contact possible. Extreme explosion hazard requires remote operation.
Water reactivity: Insoluble in water, floats on surface. No significant reaction with water.. Recommended extinguishing: AFFF, alcohol-resistant foam, CO2, dry chemical, water spray for cooling.
ERG Guide 128 recommendation: ERG 128: Initially isolate 50m in all directions. For large spills isolate 150m and evacuate downwind 800m. Highly flammable vapors will accumulate in low areas.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 128 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.