☣️ UN 2455 • CLASS 2
Methyl nitrite
Placard: Flammable Gas. 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 2455
Class: 2
Placard type: Flammable Gas
ERG: Guide 116 (check current ERG)
Isolation: ERG 116: isolate 800m all directions initially; for large spills evacuate 1600m downwind; extremely flammable, forms explosive mixtures with air
Chemical & Response Details
| Also known as | Nitrous acid methyl esterMethyl ester of nitrous acidMethylester kyseliny dusicite |
| CAS Number | 624-91-9 |
| Appearance | Colorless to pale yellow gas with a sweet, ethereal odor. Exists as a gas at room temperature and is shipped as a liquefied compressed gas. |
| Flash Point | Not applicable (gas, extremely flammable with wide flammable range) |
| Boiling Point | -12C (10F) |
| Vapor Density | 2.1 (heavier than air) |
| Water Reactivity | Decomposes slowly in water, producing methanol and nitrous acid; no violent reaction |
| Extinguishing | CO2, dry chemical, water spray for cooling containers; avoid direct water application on liquid |
| PPE | ⚠️ Level B minimum with SCBA required; chemical-resistant gloves and protective clothing; avoid all ignition sources |
| Isolation | ERG 116: isolate 800m all directions initially; for large spills evacuate 1600m downwind; extremely flammable, forms explosive mixtures with air |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- EXTREMELY FLAMMABLE gas.
- Forms explosive mixtures with air and may ignite spontaneously.
- Vapors may travel considerable distance to an ignition source and flash back.
- Containers may explode when heated.
- May polymerize violently under heat or contamination.
First actions (field-minded)
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Keep unauthorized personnel away.
- Eliminate all ignition sources; no smoking, flares, sparks, or flames.
- Stop leak if safe to do so.
- Stay upwind, uphill, and/or upstream; ventilate area.
- Consider initial evacuation for at least 800 meters (1/2 mile) downwind.
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UN 2455 — Methyl nitrite HAZMAT RADIO NOTE — UN 2455
Product: Methyl nitrite
Class 2 / Flammable Gas / ERG 116
PPE: Level B minimum with SCBA required; chemical-resistant gloves and protective clothing; avoid all ignition sources
ISOLATION: ERG 116: isolate 800m all directions initially; for large spills evacuate 1600m downwind; extremely flammable, forms explosive mixtures with air
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 2455 — Methyl nitrite
Class: 2 | Placard: Flammable Gas | ERG Guide: 116
Appearance: Colorless to pale yellow gas with a sweet, ethereal odor. Exists as a gas at room temperature and is shipped as a liquefied compressed gas.
Water Reactivity: Decomposes slowly in water, producing methanol and nitrous acid; no violent reaction
Extinguishing: CO2, dry chemical, water spray for cooling containers; avoid direct water application on liquid
PPE: Level B minimum with SCBA required; chemical-resistant gloves and protective clothing; avoid all ignition sources
Isolation: ERG 116: isolate 800m all directions initially; for large spills evacuate 1600m downwind; extremely flammable, forms explosive mixtures with air
— Key Hazards —
• EXTREMELY FLAMMABLE gas.
• Forms explosive mixtures with air and may ignite spontaneously.
• Vapors may travel considerable distance to an ignition source and flash back.
— First Actions —
• Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
• Keep unauthorized personnel away.
• Eliminate all ignition sources; no smoking, flares, sparks, or flames.
• Stop leak if safe to do so.
SOURCE: allfirefighter.com/hazmat/un/2455 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2455 Methyl nitrite Cls2 ERG116 | ERG 116: isolate 800m all directions initially; for large spills evacuate 1600m | allfirefighter.com/hazmat/un/2455SMS / 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/2455
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FAQ
EXTREMELY FLAMMABLE gas. Forms explosive mixtures with air and may ignite spontaneously. Vapors may travel considerable distance to an ignition source and flash back. Containers may explode when heated. May polymerize violently under heat or contamination.
Isolate spill or leak area for at least 100 meters (330 feet) in all directions. Keep unauthorized personnel away. Eliminate all ignition sources; no smoking, flares, sparks, or flames.
Level B minimum with SCBA required; chemical-resistant gloves and protective clothing; avoid all ignition sources
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 116 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.