☣️ UN 1546 • CLASS 6
UN 1546 — Ammonium arsenate
Placard: Toxic. ERG Guide 151. 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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UN 1546 Quick Details
UN 1546
Product name: Ammonium arsenate
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300m downwind
Common Hazards of UN 1546
- Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Containers may explode when heated.
- Runoff may pollute waterways.
Chemical Identity & Physical Properties
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1546
Extinguishing Media
Water spray to control dust, dry chemical, CO2; avoid creating runoff due to high toxicity
PPE Requirements
⚠️ Level A or B required; full-face SCBA, chemical-resistant suit, double gloves; avoid any skin contact or inhalation
Isolation & Evacuation
ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 1546 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 1546 — Ammonium arsenateHAZMAT RADIO NOTE — UN 1546
Product: Ammonium arsenate
Class 6 / Toxic / ERG 151
PPE: Level A or B required; full-face SCBA, chemical-resistant suit, double gloves; avoid any skin contact or inhalation
ISOLATION: ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300m downwind
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 1546 — Ammonium arsenate
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: White to grayish-white crystalline powder or granular solid; odorless or slight ammonia odor at room temperature.
Water Reactivity: Soluble in water; no violent reaction but dissolves to form toxic arsenic solutions
Extinguishing: Water spray to control dust, dry chemical, CO2; avoid creating runoff due to high toxicity
PPE: Level A or B required; full-face SCBA, chemical-resistant suit, double gloves; avoid any skin contact or inhalation
Isolation: ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300m downwind
— Key Hazards —
• Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
• Avoid any skin contact.
• Fire may produce irritating, corrosive and/or toxic gases.
— 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.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/1546 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1546 Ammonium arsenate Cls6 ERG151 | ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300 | allfirefighter.com/hazmat/un/1546SMS / 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/1546
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Frequently Asked Questions about UN 1546
Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive Containers may explode when heated. Runoff may pollute waterways.
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 A or B required; full-face SCBA, chemical-resistant suit, double gloves; avoid any skin contact or inhalation
Water reactivity: Soluble in water; no violent reaction but dissolves to form toxic arsenic solutions. Recommended extinguishing: Water spray to control dust, dry chemical, CO2; avoid creating runoff due to high toxicity.
ERG Guide 151 recommendation: ERG 151: isolate spill 25m all directions; large spill isolate 50m, evacuate 300m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 151 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.