UN 0129 — Lead azide, wetted
Placard: Explosive 1.1A. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0129, Lead azide wetted, is a primary explosive compound classified as a Division 1.1A explosive, meaning the entire load is capable of detonating simultaneously in a mass explosion event. It is transported wetted with water or alcohol to reduce its extreme sensitivity to shock, heat, and friction during handling and transit.
Hazard overview: Lead azide presents a mass explosion hazard in which the full quantity of material can detonate simultaneously, generating severe blast overpressure and deadly fragmentation. The dry form is extremely sensitive to heat, shock, and friction, making any loss of the wetted condition during an incident an immediate life-safety emergency.
Response guidance: Upon arrival, establish a minimum isolation perimeter of 500 meters in all directions and evacuate at least 1,600 meters downwind if fire or explosion risk is present, per ERG Guide 112. Apply water spray only to maintain the wetted state of the material; do not apply foam, CO2, or dry chemical agents to any dry lead azide.
UN 0129 Quick Details
Common Hazards of UN 0129
- 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 0129 Lead azide is a white to buff-colored, odorless crystalline powder or small crystals supplied in a wetted state with water or alcohol to suppress its detonation sensitivity.
| Also known as | Lead diazideLead(II) azidePb(N3)2Plumbous azide |
| CAS Number | 13424-46-9 |
| Appearance | White to buff-colored crystalline powder or small crystals. Odorless. Supplied wetted with water or alcohol for safety during transport and handling. |
| Flash Point | Not applicable (primary explosive solid) |
| Boiling Point | Not applicable (decomposes explosively at approximately 350C) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Stable when wetted with at least 20% water; dry material is extremely shock-sensitive and explosive |
Fireground Response Guidance — UN 0129
Extinguishing Media
PPE Requirements
Responders must wear Level A chemical protective suits with full-face SCBA, and all tools used must be rated explosion-safe, with remote handling methods employed wherever possible.
Isolation & Evacuation
First Actions for a UN 0129 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 0129 — Lead azide, 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.