UN 1546 — Ammonium arsenate
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1546 is Ammonium arsenate, a toxic hazardous material assigned to ERG Guide 151. Responders should verify the exact product with shipping papers, container markings and SDS before close action.
Hazard overview: UN 1546 presents toxic exposure hazards by inhalation, ingestion or skin contact. Fire, decomposition or runoff may produce toxic contamination and require air monitoring, isolation and decontamination.
Response guidance: For a UN 1546 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 151. Establish incident command, isolate the area, stay upwind, prevent incompatible contact and choose extinguishing or spill-control actions based on ERG, SDS and local SOP.
Firefighter training notes: Training for UN 1546 should emphasize toxic exposure routes, dust/vapor control, SCBA use, decontamination and avoiding skin contact. Use ERG 151, SDS and local SOP.
Regulatory context: Ammonium arsenate is regulated as a toxic hazardous material. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, 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 arsenate should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated toxic-material area away from food, combustibles where incompatible, heat and unauthorized access. Prevent dust release, leaks and contaminated runoff.
UN 1546 Quick Details
Common Hazards of UN 1546
- TOXIC material; may be harmful or fatal if inhaled, ingested or absorbed through skin.
- Avoid breathing vapors, dust or mist and avoid skin or eye contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may carry toxic contamination and may pollute waterways.
- Containers may rupture or explode when heated.
- Specific toxicity and absorption risk should be confirmed from shipping papers and SDS.
Chemical Identity & Physical Properties
White to grayish-white crystalline powder or granular solid; odorless or slight ammonia odor at room temperature.
| Also known as | Diammonium arsenateDiammonium hydrogen arsenateArsenic acid diammonium saltSecondary ammonium arsenate |
| CAS Number | 7784-44-3 |
| Appearance | White to grayish-white crystalline powder or granular solid; odorless or slight ammonia odor at room temperature. |
| Flash Point | Not applicable (non-combustible inorganic salt) |
| Boiling Point | Decomposes before boiling (releases ammonia and arsenic compounds above 100°C) |
| Vapor Density | Not applicable (solid with negligible vapor pressure) |
| Water Reactivity | Soluble in water; no violent reaction but dissolves to form toxic arsenic solutions |
Fireground Response Guidance — UN 1546
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, vapor, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; avoid all skin contact and contaminated dust.
Isolation & Evacuation
First Actions for a UN 1546 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.
- Avoid breathing vapors, dust or mist and avoid all skin or eye contact.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement or unknown concentration is present.
- Use ERG Guide 151, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1546 — Ammonium arsenateUse 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.