UN 0402 — Ammonium perchlorate
Placard: Explosive 1.1D. ERG Guide 112. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0402 ammonium perchlorate is a white crystalline oxidizer used in solid rocket propellants and pyrotechnics, classified as Division 1.1D due to its potential for simultaneous mass detonation under fire, shock, or confinement conditions. Although stable at ambient temperature, this odorless powder becomes highly dangerous when heated, contaminated with organics, or subjected to mechanical shock.
Hazard overview: Ammonium perchlorate is both a powerful oxidizer and a mass explosion hazard; it can sustain and accelerate fires in nearby combustible materials while simultaneously posing a catastrophic detonation risk if heated in confinement. Decomposition releases toxic chlorine and nitrogen oxide gases that present an inhalation hazard to responders.
Response guidance: ERG Guide 112 directs responders to isolate spill or fire scenes for at least 500 meters in all directions and to consider evacuating 1,600 meters if a tank or railcar is involved in fire. Small fires may be smothered with dry sand or dry chemical; large fires involving bulk ammonium perchlorate should be evacuated and allowed to burn rather than fought directly.
UN 0402 Quick Details
Common Hazards of UN 0402
- 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
Ammonium perchlorate is an odorless white crystalline solid or fine powder that is soluble in water and stable at room temperature but detonation-sensitive when heated, confined, or contaminated.
| Also known as | Perchloric acid ammonium saltAmmonium salt of perchloric acidAP |
| CAS Number | 7790-98-9 |
| Appearance | White crystalline solid or powder, odorless. Stable at room temperature but becomes hazardous when heated or subjected to shock. |
| Flash Point | Not applicable (oxidizing solid, does not burn but supports combustion) |
| Boiling Point | Not applicable (decomposes at approximately 200C/392F before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water; no violent reaction but dissolved material remains oxidizing and hazardous |
Fireground Response Guidance — UN 0402
Extinguishing Media
PPE Requirements
Level A protection is recommended for fire or large spill response; full structural firefighter protective clothing with positive-pressure SCBA is the minimum for all field operations.
Isolation & Evacuation
First Actions for a UN 0402 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 0402 — Ammonium perchlorateUse 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.