UN 3427 — Chlorobenzyl chlorides, solid
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3427 is Chlorobenzyl chlorides, solid, a toxic chlorinated aromatic material that can act as a strong irritant/lachrymator. It is used as a chemical intermediate and should be treated as a toxic corrosive solid in emergencies.
Hazard overview: UN 3427 may cause severe irritation or injury to eyes, skin and respiratory tract. Heating or fire may release hydrogen chloride and toxic chlorinated fumes. Dust or vapors can be irritating, and some material may burn but not readily.
Response guidance: For UN 3427, isolate the area, avoid dust generation and keep personnel upwind. Use dry chemical, CO2, alcohol-resistant foam or water spray for container cooling as conditions allow, while preventing contaminated runoff.
UN 3427 Quick Details
Common Hazards of UN 3427
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Combustible material: may burn but does not ignite readily.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
Chemical Identity & Physical Properties
UN 3427 is generally a solid chlorinated aromatic material; color and form vary by isomer mixture. It may have a pungent irritating odor and can release irritating vapor when heated.
| Also known as | chlorinated benzyl chloridesbenzyl chloride chlorinated derivativeschlorobenzyl chloride isomers |
| Appearance | White to off-white crystalline solid with a pungent, irritating odor. May appear as chunky or granular material at room temperature. |
| Flash Point | Not applicable (solid) |
| Boiling Point | Varies by isomer, typically 213-230C (415-446F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts slowly with water, releasing HCl; avoid prolonged water contact |
Fireground Response Guidance — UN 3427
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing with eye and face protection. Avoid skin contact and protect against dust or vapor exposure.
Isolation & Evacuation
First Actions for a UN 3427 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
📋 Copy & Share Field Card
UN 3427 — Chlorobenzyl chlorides, solidUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.