UN 0042 — Boosters, without detonator
Placard: Explosive 1.1D. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0042 refers to boosters without detonator, which are solid high explosive charges designed to amplify detonation signals from smaller initiating devices. These supplementary charges present an extreme mass explosion hazard, meaning the entire load can detonate simultaneously under the right conditions.
Hazard overview: The primary hazard of UN 0042 is a mass explosion capable of producing severe blast overpressure and high-velocity fragmentation across a wide area. These charges are sensitive to heat, shock, and friction, making any fire or mechanical disturbance an immediate life-safety threat.
Response guidance: Emergency responders must isolate a minimum of 500 meters in all directions from any incident involving UN 0042, increasing to an evacuation radius of 1,600 meters if fire or an explosion threat is present. Water applied only from maximum possible distance is the sole acceptable extinguishing agent; foam, dry chemical, and CO2 must not be used on fires involving these explosives.
UN 0042 Quick Details
Common Hazards of UN 0042
- 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 0042 boosters are typically cylindrical or rectangular solid explosive blocks that may appear yellow, white, or tan in color depending on their specific composition.
| Also known as | Explosive boostersSupplementary chargesDetonating chargesHigh explosive boosters |
| Appearance | Solid explosive charges, typically cylindrical or rectangular blocks. May be yellow, white, or tan colored depending on composition. Used to amplify detonation from smaller initiating devices. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Not applicable (decomposes/explodes) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Generally stable in water, but avoid contamination or moisture that could affect reliability |
Fireground Response Guidance — UN 0042
Extinguishing Media
PPE Requirements
Responders must wear full structural firefighting gear with SCBA, but must withdraw immediately if fire directly involves the explosive material and fight any fire only from maximum standoff distance.
Isolation & Evacuation
First Actions for a UN 0042 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 0042 — Boosters, without detonatorUse 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.