☣️ 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.
🚒☣️
⚠️ 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 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
| 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
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
- 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 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 —
• 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/1558 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1558 Arsenic Cls6 ERG152 | ERG 152: isolate spill area at least 25m in all directions; for large spills iso | allfirefighter.com/hazmat/un/1558SMS / 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/1558
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Frequently Asked Questions about 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.
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 required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure
Water reactivity: No significant reaction with water under normal conditions. Recommended extinguishing: Not applicable - use water spray to keep containers cool, CO2 or dry chemical for surrounding fires.
ERG Guide 152 recommendation: ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 300m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 152 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.