☣️ UN 1261 • CLASS 3
UN 1261 — Nitromethane
Placard: Flammable. ERG Guide 129. 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.
Nitromethane is a highly flammable liquid used as a solvent and in the production of explosives. It is miscible with water and many organic solvents.
Hazard overview: Nitromethane is highly flammable and will be easily ignited by heat, sparks, or flames. Vapors may form explosive mixtures with air.
Response guidance: In case of a spill, isolate the area with a 30-meter radius for small spills and 100 meters for large spills. For fires, evacuate the area within an 800-meter radius if a tank or rail car is involved.
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UN 1261 Quick Details
UN 1261
Product name: Nitromethane
DOT Class: 3
Placard type: Flammable
ERG Guide: 129 (check current ERG)
Initial isolation: ERG 129: Small spill isolate 30m all directions; large spill isolate 100m all directions and evacuate 800m downwind if tank/rail car involved in fire
Common Hazards of UN 1261
- 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
Nitromethane is a colorless oily liquid with a mild, fruity or disagreeable odor.
| Also known as | NitrocarbolMononitromethaneNMNitrometan |
| CAS Number | 75-52-5 |
| Appearance | Colorless oily liquid with a mild, fruity or disagreeable odor. Miscible with water and many organic solvents. |
| Flash Point | 35°C (95°F) |
| Boiling Point | 101°C (214°F) |
| Vapor Density | 2.11 (heavier than air) |
| Water Reactivity | Miscible with water; no violent reaction under normal conditions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1261
Extinguishing Media
Alcohol-resistant foam, CO2, dry chemical, water spray
PPE Requirements
⚠️ Level B minimum with SCBA; chemical-resistant gloves and suit recommended due to skin absorption potential
Wear Level B minimum personal protective equipment (PPE) with a self-contained breathing apparatus (SCBA), chemical-resistant gloves, and a suit due to skin absorption potential.
Isolation & Evacuation
ERG 129: Small spill isolate 30m all directions; large spill isolate 100m all directions and 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 129).
First Actions for a UN 1261 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 1261 — NitromethaneHAZMAT RADIO NOTE — UN 1261
Product: Nitromethane
Class 3 / Flammable / ERG 129
PPE: Level B minimum with SCBA; chemical-resistant gloves and suit recommended due to skin absorption potential
ISOLATION: ERG 129: Small spill isolate 30m all directions; large spill isolate 100m all directions 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 1261 — Nitromethane
Class: 3 | Placard: Flammable | ERG Guide: 129
Appearance: Colorless oily liquid with a mild, fruity or disagreeable odor. Miscible with water and many organic solvents.
Water Reactivity: Miscible with water; no violent reaction under normal conditions
Extinguishing: Alcohol-resistant foam, CO2, dry chemical, water spray
PPE: Level B minimum with SCBA; chemical-resistant gloves and suit recommended due to skin absorption potential
Isolation: ERG 129: Small spill isolate 30m all directions; large spill isolate 100m all directions 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 —
• 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/1261 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1261 Nitromethane Cls3 ERG129 | ERG 129: Small spill isolate 30m all directions; large spill isolate 100m all di | allfirefighter.com/hazmat/un/1261SMS / 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/nitromethane-un-1261
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Frequently Asked Questions about UN 1261
Yes, Nitromethane is highly flammable.
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.