UN 0155 — Trinitrochlorobenzene; Picryl chloride
Placard: Explosive 1.1D. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0155, Trinitrochlorobenzene (Picryl chloride), is a yellow crystalline explosive solid classified as a Class 1.1D explosive capable of mass detonation. This compound is sensitive to heat, shock, and friction, making it one of the most hazardous explosive materials encountered in transport emergencies.
Hazard overview: UN 0155 presents a mass explosion hazard in which the entire load may detonate simultaneously, producing severe blast overpressure and fragmentation capable of causing casualties at significant distances. The compound is sensitive to heat, shock, and friction, meaning that any improper handling, fire exposure, or mechanical impact can trigger detonation.
Response guidance: Responders must immediately isolate a minimum of 500 meters (1,600 feet) in all directions and expand evacuation to 1,600 meters (1 mile) if fire or detonation risk is present, per ERG Guide 112. Fighting fires involving UN 0155 is not recommended; the area should be evacuated and the incident managed from maximum safe distance.
UN 0155 Quick Details
Common Hazards of UN 0155
- Mass explosion hazard — entire load may detonate simultaneously.
- Severe blast overpressure and fragmentation.
- Sensitive to heat, shock, and friction.
- Secondary fire and debris hazard.
Chemical Identity & Physical Properties
UN 0155 is a yellow crystalline solid with no distinct odor that is stable when dry but becomes highly hazardous when subjected to heat, shock, or friction.
| Also known as | Picryl chloride2,4,6-TrinitrochlorobenzeneTNCB1-Chloro-2,4,6-trinitrobenzene |
| CAS Number | 88-88-0 |
| Appearance | Yellow crystalline solid with no distinct odor. Sensitive explosive compound that is stable when dry but highly hazardous when handled. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Decomposes before boiling; not applicable |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water, but water is used to desensitize during transport |
Fireground Response Guidance — UN 0155
Extinguishing Media
PPE Requirements
Responders handling UN 0155 incidents must wear Level B protection as a minimum with full structural firefighting gear and SCBA, while maintaining maximum possible distance from the material at all times.
Isolation & Evacuation
First Actions for a UN 0155 Incident
- CALL 911. Then call emergency response telephone number on shipping paper.
- Establish large isolation zone — minimum 500 meters in all directions.
- Stage upwind, uphill; limit personnel to essential responders only.
- Request Hazmat + law enforcement + additional resources immediately.
- Do not fight fire — evacuate and isolate; let burn if no life safety risk.
- Protect exposures only if safe and directed by command.
- Consult current ERG Guide 112 and follow SOP/SOG.
📋 Copy & Share Field Card
UN 0155 — Trinitrochlorobenzene; Picryl chlorideUse 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.