UN 0374 — Sounding devices, explosive
Placard: Explosive 1.1D. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0374 designates explosive sounding devices classified as Division 1.1D, representing a mass explosion hazard capable of simultaneously detonating an entire load with catastrophic blast overpressure and fragmentation. These devices are used in underwater acoustic signaling and seismic surveying applications and contain high-order explosive charges.
Hazard overview: A mass detonation event involving UN 0374 can produce lethal blast overpressure and high-velocity fragmentation capable of causing casualties and structural damage hundreds of meters from the source. The 1.1D classification means no fire resistance is expected between the explosive and an initiating source, making the entire quantity at risk simultaneously.
Response guidance: Immediately isolate 500 meters in all directions and evacuate at least 800 meters downwind if the material is on fire or involved in an explosion. Do not attempt to fight fires involving UN 0374 — withdraw, notify explosive ordnance disposal authorities, and allow emergency services to manage the perimeter.
UN 0374 Quick Details
Common Hazards of UN 0374
- 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 0374 sounding devices are typically cylindrical or rectangular solid units in metal or plastic casings, varying in size by manufacturer, and contain high explosive charges intended for underwater or seismic acoustic applications.
| Also known as | explosive sounding devicesseismic explosive chargesmarine explosive soundersacoustic explosive chargesexplosive sound signal devices |
| Appearance | Solid explosive devices typically housed in metal or plastic casings, used for underwater acoustic signaling or seismic surveying. Appearance varies by manufacturer but often cylindrical or rectangular packages containing high explosives. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Not applicable (explosive solid) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water, but devices are designed for underwater detonation |
Fireground Response Guidance — UN 0374
Extinguishing Media
PPE Requirements
Level B minimum with full structural firefighting gear and SCBA is required, but given the extreme fragmentation hazard, maximum standoff distance and EOD involvement are the primary protective measures.
Isolation & Evacuation
First Actions for a UN 0374 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 0374 — Sounding devices, explosiveUse 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.