☣️ UN 1439 • CLASS 5
Ammonium dichromate
Placard: Oxidizer. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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.
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Quick details
UN 1439
Class: 5
Placard type: Oxidizer
ERG: Guide 141 (check current ERG)
Isolation: ERG 141: isolate spill 25-50m all directions; large spill isolate 100m, evacuate 300m downwind if fire
Chemical & Response Details
| Also known as | Ammonium bichromateDiammonium dichromateChromic acid diammonium saltAmmonium chromate(VI) |
| CAS Number | 7789-09-5 |
| Appearance | Orange to red-orange crystalline solid with no distinct odor. Exists as dense crystals at room temperature. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Not applicable (decomposes at 170-180C/338-356F before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water; exothermic dissolution but no violent reaction. Avoid contamination with organics. |
| Extinguishing | Water spray for cooling only. Do not use foam or CO2 on bulk material. Dry sand for small fires. |
| PPE | ⚠️ Level B minimum with SCBA required. Full body protection due to carcinogenic chromium(VI) exposure risk. |
| Isolation | ERG 141: isolate spill 25-50m all directions; large spill isolate 100m, evacuate 300m downwind if fire |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- These substances will accelerate burning when involved in a fire.
- May explode from heat or contamination.
- Some may burn rapidly.
- Some will react explosively with hydrocarbons (fuels).
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- Toxic by ingestion.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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UN 1439 — Ammonium dichromate HAZMAT RADIO NOTE — UN 1439
Product: Ammonium dichromate
Class 5 / Oxidizer / ERG 141
PPE: Level B minimum with SCBA required. Full body protection due to carcinogenic chromium(VI) exposure risk.
ISOLATION: ERG 141: isolate spill 25-50m all directions; large spill isolate 100m, evacuate 300m downwind if fire
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 1439 — Ammonium dichromate
Class: 5 | Placard: Oxidizer | ERG Guide: 141
Appearance: Orange to red-orange crystalline solid with no distinct odor. Exists as dense crystals at room temperature.
Water Reactivity: Soluble in water; exothermic dissolution but no violent reaction. Avoid contamination with organics.
Extinguishing: Water spray for cooling only. Do not use foam or CO2 on bulk material. Dry sand for small fires.
PPE: Level B minimum with SCBA required. Full body protection due to carcinogenic chromium(VI) exposure risk.
Isolation: ERG 141: isolate spill 25-50m all directions; large spill isolate 100m, evacuate 300m downwind if fire
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• May explode from heat or contamination.
• Some may burn rapidly.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1439 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1439 Ammonium dichromate Cls5 ERG141 | ERG 141: isolate spill 25-50m all directions; large spill isolate 100m, evacuate | allfirefighter.com/hazmat/un/1439SMS / 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/1439
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FAQ
These substances will accelerate burning when involved in a fire. May explode from heat or contamination. Some may burn rapidly. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard. Toxic by ingestion.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum with SCBA required. Full body protection due to carcinogenic chromium(VI) exposure risk.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 141 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.