☣️ UN 1148 • CLASS 3
Diacetone alcohol
Placard: Flammable. 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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Quick details
UN 1148
Class: 3
Placard type: Flammable
ERG: Guide 129 (check current ERG)
Isolation: ERG 129: Small spill isolate 50m; large spill isolate 150m and evacuate 800m downwind if tank/rail car involved in fire
Chemical & Response Details
| Also known as | 4-Hydroxy-4-methyl-2-pentanoneDiacetoneDiketone alcohol2-Methyl-2-pentanol-4-onePyranton A |
| CAS Number | 123-42-2 |
| Appearance | Clear to pale yellow liquid with a pleasant, mild, ketone-like odor. Miscible with water and most organic solvents. |
| Flash Point | 58°C (136°F) closed cup |
| Boiling Point | 164-166°C (327-331°F) |
| Vapor Density | 4.0 (heavier than air) |
| Water Reactivity | No significant reaction; completely miscible with water |
| Extinguishing | Alcohol-resistant foam (AR-AFFF), CO2, dry chemical, water spray for cooling |
| PPE | ⚠️ Level C minimum in vapor area; Level B with SCBA if concentrations unknown or confined space entry required |
| Isolation | ERG 129: Small spill isolate 50m; large spill isolate 150m and evacuate 800m downwind if tank/rail car involved in fire |
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).
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UN 1148 — Diacetone alcohol HAZMAT RADIO NOTE — UN 1148
Product: Diacetone alcohol
Class 3 / Flammable / ERG 129
PPE: Level C minimum in vapor area; Level B with SCBA if concentrations unknown or confined space entry required
ISOLATION: ERG 129: Small spill isolate 50m; large spill isolate 150m and 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 1148 — Diacetone alcohol
Class: 3 | Placard: Flammable | ERG Guide: 129
Appearance: Clear to pale yellow liquid with a pleasant, mild, ketone-like odor. Miscible with water and most organic solvents.
Water Reactivity: No significant reaction; completely miscible with water
Extinguishing: Alcohol-resistant foam (AR-AFFF), CO2, dry chemical, water spray for cooling
PPE: Level C minimum in vapor area; Level B with SCBA if concentrations unknown or confined space entry required
Isolation: ERG 129: Small spill isolate 50m; large spill isolate 150m and 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 —
• 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/1148 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1148 Diacetone alcohol Cls3 ERG129 | ERG 129: Small spill isolate 50m; large spill isolate 150m and evacuate 800m dow | allfirefighter.com/hazmat/un/1148SMS / 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/1148
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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 C minimum in vapor area; Level B with SCBA if concentrations unknown or confined space entry required
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 129 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.