UN 1439 — Ammonium dichromate
Placard: Oxidizer. ERG Guide 141. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1439 is Ammonium dichromate, a Class 5 oxidizer assigned to ERG Guide 141. It combines oxidizer fire behavior with toxic chromium(VI) dust and runoff concerns.
Hazard overview: UN 1439 presents oxidizer, heat/contamination and toxic chromium exposure hazards. Dust, smoke and runoff should be controlled because dichromate materials can be hazardous even when no fire is present.
Response guidance: For a UN 1439 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 141. Establish incident command, isolate the area, stay upwind, prevent incompatible contact and choose extinguishing or spill-control actions based on the ERG, SDS and local SOP.
Firefighter training notes: Training for UN 1439 should emphasize oxidizer fire behavior, separation from fuels and organics, contamination control, dust avoidance, container-heating hazards and correct extinguishing decisions. Common errors include treating oxidizers like ordinary combustibles, mixing contaminated material and using incompatible cleanup methods. Use ERG 141, SDS and local SOP.
Regulatory context: Ammonium dichromate is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Ammonium dichromate should be stored in compatible oxidizer storage away from fuels, organic materials, reducing agents, acids where incompatible, heat, ignition sources and contamination. Keep containers closed, dry, clearly labeled and separated from combustible packaging or spilled residues.
UN 1439 Quick Details
Common Hazards of UN 1439
- OXIDIZER: may intensify fire and accelerate burning of combustible materials.
- May ignite combustibles such as wood, paper, oil, clothing or packaging.
- May react dangerously with fuels, organic materials, reducing agents or contamination.
- Containers may rupture or explode when heated.
- Fire may produce irritating and/or toxic gases.
- Runoff may create fire, explosion or environmental hazards.
- Dust, solution or decomposition products may irritate or injure eyes, skin or respiratory tissue.
- Hexavalent chromium compounds may present serious toxic and carcinogenic exposure concerns; avoid dust contact.
Chemical Identity & Physical Properties
Orange to red-orange crystalline solid with no distinct odor. Exists as dense crystals at room temperature.
| 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. |
Fireground Response Guidance — UN 1439
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, dust, decomposition or confined-space exposure. Wear chemical-resistant protective clothing, gloves and eye/face protection; avoid chromium(VI) dust and contaminated runoff.
Isolation & Evacuation
First Actions for a UN 1439 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Keep combustibles, fuels, organics, reducing agents and contaminated materials away from the spill.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust clouds and prevent runoff from contacting combustibles or drains when possible.
- Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
- Isolate the spill or fire area and expand the perimeter if large quantities, contamination, heating or container involvement are present.
- Use ERG Guide 141, shipping papers, SDS and local SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1439 — Ammonium dichromateUse 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.