UN 0159 — Powder cake, wetted
Placard: Explosive 1.3C. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0159, Powder Cake Wetted, is a compressed block or cake of explosive powder that has been deliberately wetted with water or alcohol to reduce its sensitivity during transport and handling. Although desensitized in its wetted state, this Class 1.3C explosive remains a serious fire and deflagration hazard if allowed to dry out.
Hazard overview: UN 0159 presents a fire and burning hazard capable of intense heat release, possible fragment projection, and deflagration that can initiate surrounding materials. Drying of the wetted cake dramatically increases the explosion hazard, making moisture maintenance critical at all times during an incident.
Response guidance: Emergency responders should isolate the area in all directions to a minimum of 500 meters and expand evacuation to a 1,600-meter radius if the material is involved in fire or a large spill occurs. The priority action is to keep the material continuously wet using water fog or spray, as allowing it to dry significantly escalates the explosive risk.
UN 0159 Quick Details
Common Hazards of UN 0159
- Fire and burning hazard — not mass explosion.
- Intense heat and possible fragment projection.
- May deflagrate and initiate other materials.
- Smoke and toxic combustion products.
Chemical Identity & Physical Properties
UN 0159 appears as a gray to black compressed solid cake or block with a visibly dampened surface resulting from intentional wetting with water or alcohol.
| Also known as | Powder cakeWetted powder cakeDampened explosive powderMoistened propellant powder |
| Appearance | Compressed cake or block of explosive powder wetted with water or alcohol to reduce sensitivity. Typically gray to black solid material with dampened surface. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Not applicable (explosive solid) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Desensitized by water; drying increases explosion hazard |
Fireground Response Guidance — UN 0159
Extinguishing Media
PPE Requirements
Responders must use Level B protection at minimum with full structural firefighting gear and SCBA, and should conduct all operations remotely whenever possible.
Isolation & Evacuation
First Actions for a UN 0159 Incident
- CALL 911. Then call emergency response telephone number on shipping paper.
- Isolate area; stage upwind — fire and fragment hazard.
- Request Hazmat + law enforcement.
- Control ignition sources; deny entry.
- Consult current ERG Guide 112 and follow SOP/SOG.
📋 Copy & Share Field Card
UN 0159 — Powder cake, 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.