UN 0373 — Signal devices, hand
Placard: Explosive 1.4S. ERG Guide 114. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0373 covers hand-held signal devices classified as Division 1.4S explosives, meaning any explosive effect is confined to the package with negligible blast hazard to the surrounding area. These pyrotechnic devices produce colored flames or smoke and are commonly used for distress signaling in maritime, aviation, and wilderness rescue contexts.
Hazard overview: UN 0373 presents a minor, localized blast or fire hazard with effects limited to the immediate package, not the surrounding cargo or environment. Deflagration rather than detonation is the expected failure mode, though burning pyrotechnic compositions can project hot particles and produce toxic smoke.
Response guidance: Isolate the spill or leak area for at least 50 meters in all directions and extend to 800 meters if fire or explosion is involved. Apply water spray, foam, dry chemical, or CO2 to small fires, and use water from a safe distance for larger incidents while wearing positive pressure SCBA.
UN 0373 Quick Details
Common Hazards of UN 0373
- 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 0373 devices are small cylindrical or tube-shaped units, typically red or orange in color, containing pyrotechnic compositions designed to ignite and produce visible colored flames or smoke.
| Also known as | Hand-held signal devicesHandheld flaresMarine distress signalsHand signal flaresPyrotechnic signal devices |
| Appearance | Small cylindrical or tube-shaped devices, typically red or orange colored, containing pyrotechnic compositions that produce colored flames or smoke when ignited. |
| Flash Point | Not applicable (pyrotechnic device) |
| Boiling Point | Not applicable (pyrotechnic device) |
| Vapor Density | Not applicable (solid pyrotechnic) |
| Water Reactivity | May react with water depending on composition; keep dry during storage |
Fireground Response Guidance — UN 0373
Extinguishing Media
PPE Requirements
Structural firefighters' protective clothing with positive pressure SCBA is recommended, as the pyrotechnic compositions can emit toxic combustion products and project hot debris.
Isolation & Evacuation
First Actions for a UN 0373 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 0373 — Signal devices, handUse 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.