☣️ UN 1621 • CLASS 6
UN 1621 — London purple
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.
London purple is a highly toxic substance that can be fatal if inhaled, ingested, or absorbed through skin. It is a purple to violet-colored powder or crystalline solid with an odorless to slight metallic odor.
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 downwind areas if airborne. Use water spray, dry chemical, sand for fire control.
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UN 1621 Quick Details
UN 1621
Product name: London purple
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: isolate spill 25m all directions; if large spill isolate 50m; evacuate downwind areas if airborne
Common Hazards of UN 1621
- 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
Purple to violet-colored powder or crystalline solid. Odorless to slight metallic odor. Solid at room temperature.
| Also known as | Arsenite of limeCalcium arseniteLondon purple insecticideArsenical dustPurple dye |
| CAS Number | 8028-73-7 |
| Appearance | Purple to violet-colored powder or crystalline solid. Odorless to slight metallic odor. Solid at room temperature. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Slowly soluble in water, may release toxic arsenic compounds |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1621
Extinguishing Media
Water spray, dry chemical, sand; avoid creating dust clouds
PPE Requirements
⚠️ Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid skin contact completely
Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid skin contact completely.
Isolation & Evacuation
ERG 151: isolate spill 25m all directions; if large spill isolate 50m; evacuate downwind areas if airborne
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 1621 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 1621 — London purpleHAZMAT RADIO NOTE — UN 1621
Product: London purple
Class 6 / Toxic / ERG 151
PPE: Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid skin contact completely
ISOLATION: ERG 151: isolate spill 25m all directions; if large spill isolate 50m; evacuate downwind areas if airborne
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 1621 — London purple
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: Purple to violet-colored powder or crystalline solid. Odorless to slight metallic odor. Solid at room temperature.
Water Reactivity: Slowly soluble in water, may release toxic arsenic compounds
Extinguishing: Water spray, dry chemical, sand; avoid creating dust clouds
PPE: Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid skin contact completely
Isolation: ERG 151: isolate spill 25m all directions; if large spill isolate 50m; evacuate downwind areas if airborne
— 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/1621 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1621 London purple Cls6 ERG151 | ERG 151: isolate spill 25m all directions; if large spill isolate 50m; evacuate | allfirefighter.com/hazmat/un/1621SMS / 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/london-purple-un-1621
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Frequently Asked Questions about UN 1621
No, UN 1621 is not flammable.
Yes, UN 1621 is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.
Isolate spill 25m all directions, evacuate downwind areas if airborne.
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.