UN 0391 — RDX and HMX mixtures, wetted
Placard: Explosive 1.1D. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0391 consists of mixtures of RDX and HMX military-grade secondary explosives that have been wetted with water or alcohol to reduce detonation sensitivity during transport. Classified as Division 1.1D, these white to pale yellow crystalline solids represent a mass explosion hazard capable of simultaneously detonating an entire shipment.
Hazard overview: A detonation of UN 0391 generates severe blast overpressure and high-velocity fragmentation that can cause catastrophic structural damage and casualties across a wide radius. Loss of the wetting agent through evaporation or leakage significantly increases sensitivity to shock, heat, and friction.
Response guidance: Per ERG Guide 112, isolate the scene 800 meters in all directions immediately and consider evacuating a 1,600-meter radius if fire or detonation threat is present. If fire exposure is unavoidable, apply flooding quantities of water from maximum safe distance solely to keep the explosive material wet and prevent drying.
UN 0391 Quick Details
Common Hazards of UN 0391
- 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
RDX/HMX wetted mixtures appear as white to pale yellow odorless or faintly characteristic-smelling crystalline solids, stabilized with water or alcohol to reduce impact and friction sensitivity.
| Also known as | RDX/HMX mixtureCyclotrimethylenetrinitramine and Cyclotetramethylenetetranitramine mixtureOctogen and Hexogen mixturewetted high explosives mixture |
| Appearance | White to pale yellow crystalline solid, wetted with water or alcohol to reduce sensitivity. Odorless or slight characteristic odor. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water; wetting agent used for stabilization |
Fireground Response Guidance — UN 0391
Extinguishing Media
PPE Requirements
Full protective clothing with positive-pressure SCBA is mandatory; personnel should approach only when absolutely necessary for confirmed life-safety operations.
Isolation & Evacuation
First Actions for a UN 0391 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 0391 — RDX and HMX mixtures, wettedUse 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.