☣️ UN 1166 • CLASS 3
UN 1166 — Dioxolane
Placard: Flammable. ERG Guide 127. 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.
Dioxolane is a highly flammable liquid with a mild, ether-like odor, requiring careful handling to prevent accidents. It is commonly used as a solvent and intermediate in various chemical reactions.
Hazard overview: Dioxolane is highly flammable and can be easily ignited by heat, sparks, or flames, forming explosive mixtures with air. Prolonged exposure to its vapors can also be hazardous to human health.
Response guidance: In case of a dioxolane spill, evacuate the area immediately and use alcohol-resistant foam or CO2 to extinguish the fire. Wear Level B minimum PPE with SCBA to prevent inhalation of toxic vapors.
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UN 1166 Quick Details
UN 1166
Product name: Dioxolane
DOT Class: 3
Placard type: Flammable
ERG Guide: 127 (check current ERG)
Initial isolation: ERG 127: Small spill isolate 30m all directions; large spill isolate 150m all directions, evacuate 800m downwind if tank/rail car involved in fire
Common Hazards of UN 1166
- 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
Dioxolane is a colorless liquid with low viscosity and a mild, ether-like odor, existing as a mobile liquid at room temperature.
| Also known as | 1,3-Dioxolane1,3-DioxacyclopentaneEthylene glycol formalGlycol methylene ether |
| CAS Number | 646-06-0 |
| Appearance | Colorless liquid with a mild, ether-like odor. Exists as a mobile liquid at room temperature with low viscosity. |
| Flash Point | 2°C (36°F) |
| Boiling Point | 78°C (172°F) |
| Vapor Density | 2.6 (heavier than air) |
| Water Reactivity | No significant reaction with water; miscible in water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1166
Extinguishing Media
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 for spill response
Level B minimum PPE with SCBA is required for spill response, and a full chemical-resistant suit is necessary for handling large spills.
Isolation & Evacuation
ERG 127: Small spill isolate 30m all directions; large spill isolate 150m all directions, evacuate 800m downwind if tank/rail car involved in fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 127).
First Actions for a UN 1166 Incident
- 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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📋 Copy & Share Field Card
UN 1166 — DioxolaneHAZMAT RADIO NOTE — UN 1166
Product: Dioxolane
Class 3 / Flammable / ERG 127
PPE: Level B minimum with SCBA required in vapor areas; full chemical-resistant suit for spill response
ISOLATION: ERG 127: Small spill isolate 30m all directions; large spill isolate 150m all directions, evacuate 800m 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 1166 — Dioxolane
Class: 3 | Placard: Flammable | ERG Guide: 127
Appearance: Colorless liquid with a mild, ether-like odor. Exists as a mobile liquid at room temperature with low viscosity.
Water Reactivity: No significant reaction with water; miscible in water
Extinguishing: Alcohol-resistant foam, CO2, dry chemical, water spray for cooling
PPE: Level B minimum with SCBA required in vapor areas; full chemical-resistant suit for spill response
Isolation: ERG 127: Small spill isolate 30m all directions; large spill isolate 150m all directions, evacuate 800m downwind if tank/rail car involved in fire
— 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 —
• 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.
SOURCE: allfirefighter.com/hazmat/un/1166 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1166 Dioxolane Cls3 ERG127 | ERG 127: Small spill isolate 30m all directions; large spill isolate 150m all di | allfirefighter.com/hazmat/un/1166SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/dioxolane-un-1166
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Frequently Asked Questions about UN 1166
Yes, Dioxolane is highly flammable and can be easily ignited by heat, sparks, or flames.
Level B minimum PPE with SCBA is required for spill response, and a full chemical-resistant suit is necessary for handling large spills.
Use alcohol-resistant foam, CO2, or dry chemical to extinguish the fire, and wear Level B minimum PPE with SCBA to prevent inhalation of toxic vapors.
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.