☣️ UN 1622 • CLASS 6
UN 1622 — Magnesium arsenate
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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.
Magnesium arsenate is a highly toxic substance that can be fatal if inhaled, ingested, or absorbed through skin. It is a white or grayish-white odorless powder or crystalline solid at room temperature.
Hazard overview: Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. Avoid any skin contact.
Response guidance: Isolate spill 25m all directions, evacuate immediate area and downwind if airborne powder suspected. Use water spray, fog, or dry chemical for fire control.
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UN 1622 Quick Details
UN 1622
Product name: Magnesium arsenate
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: isolate spill 25m all directions; isolate 50m if large spill; evacuate immediate area and downwind if airborne powder suspected
Common Hazards of UN 1622
- 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
White or grayish-white odorless powder or crystalline solid at room temperature. May appear as granules or lumps.
| Also known as | Trimagnesium diarsenateMagnesium arsenate tribasicArsenate of magnesiumMagnesium salt of arsenic acid |
| CAS Number | 7784-36-3 |
| Appearance | White or grayish-white odorless powder or crystalline solid at room temperature. May appear as granules or lumps. |
| Flash Point | Not applicable (inorganic solid, non-flammable) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid with negligible vapor pressure) |
| Water Reactivity | Slightly soluble in water; no violent reaction but may release toxic arsenic compounds over time |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1622
Extinguishing Media
Water spray, fog, or dry chemical suitable; no special foam restrictions for fire control
PPE Requirements
⚠️ Level B minimum; SCBA mandatory; full chemical-resistant suit required; avoid all skin contact due to extreme toxicity
Level B minimum; SCBA mandatory; full chemical-resistant suit required; avoid all skin contact due to extreme toxicity.
Isolation & Evacuation
ERG 151: isolate spill 25m all directions; isolate 50m if large spill; evacuate immediate area and downwind if airborne powder suspected
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 1622 Incident
- 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 1622 — Magnesium arsenateHAZMAT RADIO NOTE — UN 1622
Product: Magnesium arsenate
Class 6 / Toxic / ERG 151
PPE: Level B minimum; SCBA mandatory; full chemical-resistant suit required; avoid all skin contact due to extreme toxicity
ISOLATION: ERG 151: isolate spill 25m all directions; isolate 50m if large spill; evacuate immediate area and downwind if airborne powder suspected
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 1622 — Magnesium arsenate
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: White or grayish-white odorless powder or crystalline solid at room temperature. May appear as granules or lumps.
Water Reactivity: Slightly soluble in water; no violent reaction but may release toxic arsenic compounds over time
Extinguishing: Water spray, fog, or dry chemical suitable; no special foam restrictions for fire control
PPE: Level B minimum; SCBA mandatory; full chemical-resistant suit required; avoid all skin contact due to extreme toxicity
Isolation: ERG 151: isolate spill 25m all directions; isolate 50m if large spill; evacuate immediate area and downwind if airborne powder suspected
— 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 —
• 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.
SOURCE: allfirefighter.com/hazmat/un/1622 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1622 Magnesium arsenate Cls6 ERG151 | ERG 151: isolate spill 25m all directions; isolate 50m if large spill; evacuate | allfirefighter.com/hazmat/un/1622SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/magnesium-arsenate-un-1622
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Frequently Asked Questions about UN 1622
No, UN 1622 is not flammable.
Yes, UN 1622 is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.
Isolate spill 25m all directions, evacuate immediate area and downwind if airborne powder suspected.
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.