☣️ UN 2605 • CLASS 6
Methoxymethyl isocyanate
Placard: Toxic. 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.
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Quick details
UN 2605
Class: 6
Placard type: Toxic
ERG: Guide 155 (check current ERG)
Isolation: ERG 155: isolate spill or leak area immediately for at least 50m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation for 800m
Chemical & Response Details
| Also known as | Methoxymethyl isocyanateMMICIsocyanic acid methoxymethyl esterMethoxymethanyl isocyanate |
| CAS Number | 39815-82-4 |
| Appearance | Colorless to pale yellow liquid with a pungent, acrid odor. Highly reactive organic compound in the isocyanate family. |
| Flash Point | -7C (19F) |
| Boiling Point | 85-90C (185-194F) |
| Vapor Density | 2.5 (heavier than air) |
| Water Reactivity | Reacts with water to release carbon dioxide and heat; avoid contact with moisture |
| Extinguishing | Dry chemical, CO2, or dry sand; alcohol-resistant foam may be used with caution; avoid direct water streams |
| PPE | ⚠️ Level A recommended; full-encapsulating chemical protective suit with SCBA; isocyanates are highly toxic by inhalation and skin contact |
| Isolation | ERG 155: isolate spill or leak area immediately for at least 50m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation for 800m |
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 form explosive mixtures with air: indoors, outdoors and sewers explosion hazards.
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapors may travel to source of ignition and flash back.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
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 in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 2605 — Methoxymethyl isocyanate HAZMAT RADIO NOTE — UN 2605
Product: Methoxymethyl isocyanate
Class 6 / Toxic / ERG 155
PPE: Level A recommended; full-encapsulating chemical protective suit with SCBA; isocyanates are highly toxic by inhalation and skin contact
ISOLATION: ERG 155: isolate spill or leak area immediately for at least 50m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation for 800m
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 2605 — Methoxymethyl isocyanate
Class: 6 | Placard: Toxic | ERG Guide: 155
Appearance: Colorless to pale yellow liquid with a pungent, acrid odor. Highly reactive organic compound in the isocyanate family.
Water Reactivity: Reacts with water to release carbon dioxide and heat; avoid contact with moisture
Extinguishing: Dry chemical, CO2, or dry sand; alcohol-resistant foam may be used with caution; avoid direct water streams
PPE: Level A recommended; full-encapsulating chemical protective suit with SCBA; isocyanates are highly toxic by inhalation and skin contact
Isolation: ERG 155: isolate spill or leak area immediately for at least 50m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation for 800m
— Key Hazards —
• HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
• Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards.
• Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
— 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/2605 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2605 Methoxymethyl isocyanate Cls6 ERG155 | allfirefighter.com/hazmat/un/2605SMS / 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/2605
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FAQ
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas Vapors may travel to source of ignition and flash back. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
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 A recommended; full-encapsulating chemical protective suit with SCBA; isocyanates are highly toxic by inhalation and skin contact
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 155 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.