☣️ UN 3428 • CLASS 6
UN 3428 — Chloro-methylphenyl isocyanate, solid
Placard: Toxic. ERG Guide 156. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
UN 3428 is Chloro-methylphenyl isocyanate, solid, a toxic and corrosive isocyanate compound. Moisture contact can produce heat, carbon dioxide and irritating or toxic decomposition products.
Hazard overview: UN 3428 can injure the respiratory tract, skin and eyes, and isocyanate vapors or dust may cause severe sensitization or irritation. Water or moisture may react with the material, and heating can generate toxic and corrosive gases.
Response guidance: For UN 3428, isolate the release, keep the material dry and avoid direct water contact unless directed by specialists. Use dry chemical, CO2 or dry sand when compatible, cool exposures from a protected distance and prevent runoff.
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UN 3428 Quick Details
UN 3428
Product name: Chloro-methylphenyl isocyanate, solid
DOT Class: 6
Placard type: Toxic
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: Isolate spill area immediate 25m in all directions. For large spills isolate 50m and consider evacuation 300m downwind.
Common Hazards of UN 3428
- Combustible material: may burn but does not ignite readily.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
- 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.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
- TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
Chemical Identity & Physical Properties
UN 3428 is a solid isocyanate material; appearance varies from pale solid to crystalline or granular forms. It may have a sharp, irritating odor and can release hazardous vapors when warmed.
| Also known as | Chloro-methylphenyl isocyanateIsocyanic acid, Chloro-methylphenyl ester4-Methyl-3-chlorophenyl isocyanate3-Chloro-4-cresyl isocyanate |
| CAS Number | 28479-22-3 |
| Appearance | White to light tan crystalline solid with a sharp, pungent odor. Combustible at elevated temperatures. |
| Flash Point | 113°C (235°F) |
| Boiling Point | Decomposes before boiling |
| Vapor Density | Not applicable (solid at room temperature) |
| Water Reactivity | Reacts with water liberating toxic and corrosive gases including hydrogen chloride and carbon dioxide. Avoid water contact. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3428
Extinguishing Media
Dry chemical, CO2, dry sand. Do not use water or foam directly on material.
PPE Requirements
⚠️ Level B minimum with SCBA required. Full chemical resistant suit for spill response. Avoid all skin and eye contact.
Use SCBA and full chemical-resistant protective clothing. Level A may be needed for significant dust, vapor or unknown concentration; avoid all skin and respiratory exposure.
Isolation & Evacuation
ERG 156: Isolate spill area immediate 25m in all directions. For large spills isolate 50m and consider evacuation 300m downwind.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).
First Actions for a UN 3428 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 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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📋 Copy & Share Field Card
UN 3428 — Chloro-methylphenyl isocyanate, solidHAZMAT RADIO NOTE — UN 3428
Product: Chloro-methylphenyl isocyanate, solid
Class 6 / Toxic / ERG 156
PPE: Level B minimum with SCBA required. Full chemical resistant suit for spill response. Avoid all skin and eye contact.
ISOLATION: ERG 156: Isolate spill area immediate 25m in all directions. For large spills isolate 50m and consider evacuation 300m downwind.
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 3428 — Chloro-methylphenyl isocyanate, solid
Class: 6 | Placard: Toxic | ERG Guide: 156
Appearance: White to light tan crystalline solid with a sharp, pungent odor. Combustible at elevated temperatures.
Water Reactivity: Reacts with water liberating toxic and corrosive gases including hydrogen chloride and carbon dioxide. Avoid water contact.
Extinguishing: Dry chemical, CO2, dry sand. Do not use water or foam directly on material.
PPE: Level B minimum with SCBA required. Full chemical resistant suit for spill response. Avoid all skin and eye contact.
Isolation: ERG 156: Isolate spill area immediate 25m in all directions. For large spills isolate 50m and consider evacuation 300m downwind.
— Key Hazards —
• Combustible material: may burn but does not ignite readily.
• Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
• When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
— 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 in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/chloro-methylphenyl-un-3428 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3428 Chloro-methylphenyl isocyanate, solid Cls6 ERG156 | allfirefighter.com/hazmat/un/chloro-methylphenyl-un-3428SMS / 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/chloro-methylphenyl-un-3428
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Frequently Asked Questions about UN 3428
UN 3428 is Chloro-methylphenyl isocyanate, solid. It should be identified from shipping papers, markings and the SDS before responders work near the release.
ERG Guide 156 applies to UN 3428 for initial isolation, protective actions and first-response guidance.
UN 3428 is not primarily classified as flammable, but fire may produce toxic or corrosive gases and containers may become dangerous when heated.
Use SCBA and full chemical-resistant protective clothing. Level A may be needed for significant dust, vapor or unknown concentration; avoid all skin and respiratory exposure.
UN 3428 can injure the respiratory tract, skin and eyes, and isocyanate vapors or dust may cause severe sensitization or irritation.
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.