UN 0257 — Fuzes, detonating
Placard: Explosive 1.4B. ERG Guide 114. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0257 covers detonating fuzes, also known as detonator fuzes or blasting fuzes, which are metallic or plastic cylindrical devices containing small explosive charges classified as Explosive 1.4B. These articles present a localized blast and fire hazard with potential for deflagration and smoke generation when involved in fire or heat exposure.
Hazard overview: UN 0257 detonating fuzes present a minor but real blast hazard with localized burning or deflagration possible if exposed to heat, flame, or shock. Smoke and heat produced during burning may pose secondary risks to responders approaching without adequate protection.
Response guidance: Emergency responders should isolate the area at least 200 meters in all directions and increase isolation to 500 meters with an 800-meter evacuation radius if large quantities are involved in fire. Water spray or foam may be applied from a safe distance for fire control, but direct approach to burning articles must be avoided.
UN 0257 Quick Details
Common Hazards of UN 0257
- Minor blast or fire hazard — limited effect.
- Localized burning or deflagration possible.
- Smoke and heat from burning.
- Low mass explosion risk under normal conditions.
Chemical Identity & Physical Properties
UN 0257 detonating fuzes are solid cylindrical assemblies constructed of metal or plastic in various colors depending on whether they are manufactured to military or commercial specifications.
| Also known as | Detonating fuzesDetonator fuzesBlasting fuzesExplosive fuzes |
| Appearance | Metallic or plastic cylindrical devices containing small explosive charges. Typically solid assemblies in various colors depending on manufacturer and military/commercial specifications. |
| Flash Point | Not applicable (explosive article) |
| Boiling Point | Not applicable (explosive article) |
| Vapor Density | Not applicable (solid article) |
| Water Reactivity | No significant reaction with water, though moisture may degrade some fuze components over time |
Fireground Response Guidance — UN 0257
Extinguishing Media
PPE Requirements
Responders handling UN 0257 incidents must wear full protective clothing and self-contained breathing apparatus (SCBA), approaching only from upwind or a protected location.
Isolation & Evacuation
First Actions for a UN 0257 Incident
- CALL 911. Notify law enforcement.
- Isolate area; keep unauthorized personnel away.
- Stage upwind; eliminate ignition sources.
- Request Hazmat + law enforcement.
- Consult current ERG Guide 114 and follow SOP/SOG.
📋 Copy & Share Field Card
UN 0257 — Fuzes, detonatingUse 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.