☣️ UN 0420 • CLASS 1
UN 0420 — Flares, aerial
Placard: Explosive 1.1G. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
Advertisement
UN 0420 Quick Details
UN 0420
Product name: Flares, aerial
DOT Class: 1
Placard type: Explosive 1.1G
ERG Guide: 112 (check current ERG)
Initial isolation: ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) in all directions and consider initial evacuation for 800m in all directions
Common Hazards of UN 0420
- 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
| Also known as | Pyrotechnic flaresSignal flaresIlluminating flaresAerial signalsDistress flares |
| Appearance | Cylindrical pyrotechnic devices containing metal salts and oxidizers; typically red, white, or orange colored composition; solid state at room temperature. |
| Flash Point | Not applicable (pyrotechnic composition ignites via chemical reaction, not vaporization) |
| Boiling Point | Not applicable (decomposes/burns rather than boils) |
| Vapor Density | Not applicable (solid pyrotechnic device) |
| Water Reactivity | May contain reactive metals or oxidizers; avoid water on burning flares as it may cause violent spattering or intensify reaction |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 0420
Extinguishing Media
DO NOT use water or foam; use dry sand, dry chemical, or CO2 at safe distance; flooding with large volumes of water from unmanned positions may be used if fire spreads
PPE Requirements
⚠️ Level B minimum with full structural firefighting gear; SCBA required; maintain maximum distance; use unmanned hose holders or monitor nozzles; withdraw immediately if rising sound from venting safety devices or discoloration of tank
Isolation & Evacuation
ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) in all directions and consider initial evacuation for 800m in all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 112).
First Actions for a UN 0420 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.
Advertisement
📋 Copy & Share Field Card
UN 0420 — Flares, aerialHAZMAT RADIO NOTE — UN 0420
Product: Flares, aerial
Class 1 / Explosive 1.1G / ERG 112
PPE: Level B minimum with full structural firefighting gear; SCBA required; maintain maximum distance; use unmanned hose holders or monitor nozzles; withdraw immediately if rising sound from venting safety devices or discoloration of tank
ISOLATION: ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) in all directions and consider initial evacuation for 800m in all directions
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 0420 — Flares, aerial
Class: 1 | Placard: Explosive 1.1G | ERG Guide: 112
Appearance: Cylindrical pyrotechnic devices containing metal salts and oxidizers; typically red, white, or orange colored composition; solid state at room temperature.
Water Reactivity: May contain reactive metals or oxidizers; avoid water on burning flares as it may cause violent spattering or intensify reaction
Extinguishing: DO NOT use water or foam; use dry sand, dry chemical, or CO2 at safe distance; flooding with large volumes of water from unmanned positions may be used if fire spreads
PPE: Level B minimum with full structural firefighting gear; SCBA required; maintain maximum distance; use unmanned hose holders or monitor nozzles; withdraw immediately if rising sound from venting safety devices or discoloration of tank
Isolation: ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) in all directions and consider initial evacuation for 800m in all directions
— Key Hazards —
• Mass explosion hazard — entire load may detonate simultaneously.
• Severe blast overpressure and fragmentation.
• Sensitive to heat, shock, and friction.
— First Actions —
• 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.
SOURCE: allfirefighter.com/hazmat/un/0420 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN0420 Flares, aerial Cls1 ERG112 | ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved | allfirefighter.com/hazmat/un/0420SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/0420
Related UN Numbers in Class 1
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
Advertisement
Frequently Asked Questions about UN 0420
Mass explosion hazard — entire load may detonate simultaneously. Severe blast overpressure and fragmentation. Sensitive to heat, shock, and friction. Secondary fire and debris hazard.
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.
Level B minimum with full structural firefighting gear; SCBA required; maintain maximum distance; use unmanned hose holders or monitor nozzles; withdraw immediately if rising sound from venting safety devices or discoloration of tank
Water reactivity: May contain reactive metals or oxidizers; avoid water on burning flares as it may cause violent spattering or intensify reaction. Recommended extinguishing: DO NOT use water or foam; use dry sand, dry chemical, or CO2 at safe distance; flooding with large volumes of water from unmanned positions may be used if fire spreads.
ERG Guide 112 recommendation: ERG 112: Isolate 500m (1640 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) in all directions and consider initial evacuation for 800m in all directions
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 112 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.