☣️ UN 2458 • CLASS 3
Hexadiene
Placard: Flammable. 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.
Advertisement
Quick details
UN 2458
Class: 3
Placard type: Flammable
ERG: Guide 130 (check current ERG)
Isolation: ERG 130: Isolate spill 50m all directions; for large spills consider evacuation 300m downwind; in fire isolate 800m and consider evacuation 800m all directions
Chemical & Response Details
| Also known as | 1,5-HexadieneHexa-1,5-dieneDiallylBiallyl |
| CAS Number | 592-48-3 |
| Appearance | Colorless liquid with a mild hydrocarbon odor. Lighter than water and insoluble in water. |
| Flash Point | -26°C (-15°F) |
| Boiling Point | 59-60°C (138-140°F) |
| Vapor Density | 2.8 (heavier than air) |
| Water Reactivity | No significant reaction; insoluble in water |
| Extinguishing | Alcohol-resistant foam, dry chemical, CO2; water spray for cooling |
| PPE | ⚠️ Level B minimum with SCBA; fire-resistant clothing and thermal protection in fire conditions |
| Isolation | ERG 130: Isolate spill 50m all directions; for large spills consider evacuation 300m downwind; in fire isolate 800m and consider evacuation 800m all directions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
First actions (field-minded)
- 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).
Advertisement
📋 Copy & Share
UN 2458 — Hexadiene HAZMAT RADIO NOTE — UN 2458
Product: Hexadiene
Class 3 / Flammable / ERG 130
PPE: Level B minimum with SCBA; fire-resistant clothing and thermal protection in fire conditions
ISOLATION: ERG 130: Isolate spill 50m all directions; for large spills consider evacuation 300m downwind; in fire isolate 800m and consider evacuation 800m all directions
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 2458 — Hexadiene
Class: 3 | Placard: Flammable | ERG Guide: 130
Appearance: Colorless liquid with a mild hydrocarbon odor. Lighter than water and insoluble in water.
Water Reactivity: No significant reaction; insoluble in water
Extinguishing: Alcohol-resistant foam, dry chemical, CO2; water spray for cooling
PPE: Level B minimum with SCBA; fire-resistant clothing and thermal protection in fire conditions
Isolation: ERG 130: Isolate spill 50m all directions; for large spills consider evacuation 300m downwind; in fire isolate 800m and consider evacuation 800m all directions
— 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/2458 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2458 Hexadiene Cls3 ERG130 | ERG 130: Isolate spill 50m all directions; for large spills consider evacuation | allfirefighter.com/hazmat/un/2458SMS / 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/2458
Advertisement
FAQ
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; fire-resistant clothing and thermal protection in fire conditions
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 130 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.