☣️ UN 1558 • CLASS 6
UN 1558 — Arsenic
Placard: Toxic. ERG Guide 152. 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.
Arsenic is a highly toxic substance that can be fatal if inhaled, ingested or absorbed through skin. It is a brittle crystalline solid at room temperature and may appear as a black or yellow powder depending on form.
Hazard overview: Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. Contact with molten substance may cause severe burns to skin and eyes.
Response guidance: Use Level A PPE and isolate spill area at least 25m in all directions. For large spills, isolate 50m and consider evacuation of 300m downwind.
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UN 1558 Quick Details
UN 1558
Product name: Arsenic
DOT Class: 6
Placard type: Toxic
ERG Guide: 152 (check current ERG)
Initial isolation: ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 300m downwind
Common Hazards of UN 1558
- Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
- Contact with molten substance may cause severe burns to skin and eyes.
- 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
- Combustible material: may burn but does not ignite readily.
- Containers may explode when heated.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
Chemical Identity & Physical Properties
Steel-grey or tin-white, odorless, brittle crystalline solid at room temperature. May appear as a black or yellow powder depending on form.
| Also known as | Metallic arsenicArsenic metalGrey arsenicElemental arsenic |
| CAS Number | 7440-38-2 |
| Appearance | Steel-grey or tin-white, odorless, brittle crystalline solid at room temperature. May appear as a black or yellow powder depending on form. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | 613C (1135F) - sublimes without melting |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water under normal conditions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1558
Extinguishing Media
Not applicable - use water spray to keep containers cool, CO2 or dry chemical for surrounding fires
PPE Requirements
⚠️ Level A required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure
Level A required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure
Isolation & Evacuation
ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 300m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 152).
First Actions for a UN 1558 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 1558 — ArsenicHAZMAT RADIO NOTE — UN 1558
Product: Arsenic
Class 6 / Toxic / ERG 152
PPE: Level A required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure
ISOLATION: ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 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 1558 — Arsenic
Class: 6 | Placard: Toxic | ERG Guide: 152
Appearance: Steel-grey or tin-white, odorless, brittle crystalline solid at room temperature. May appear as a black or yellow powder depending on form.
Water Reactivity: No significant reaction with water under normal conditions
Extinguishing: Not applicable - use water spray to keep containers cool, CO2 or dry chemical for surrounding fires
PPE: Level A required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure
Isolation: ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 300m downwind
— Key Hazards —
• Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— 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/arsenic-un-1558 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1558 Arsenic Cls6 ERG152 | ERG 152: isolate spill area at least 25m in all directions; for large spills iso | allfirefighter.com/hazmat/un/arsenic-un-1558SMS / 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/arsenic-un-1558
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Frequently Asked Questions about UN 1558
Yes, UN 1558 Arsenic is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.
Level A PPE is required, including full-face SCBA and chemical-resistant suit.
Isolate the spill area at least 50m in all directions and consider evacuation of 300m downwind.
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.