☣️ UN 1558 • CLASS 6
Arsenic
Placard: Toxic. 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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Quick details
UN 1558
Class: 6
Placard type: Toxic
ERG: Guide 152 (check current ERG)
Isolation: ERG 152: isolate spill area at least 25m in all directions; for large spills isolate 50m and consider evacuation of 300m downwind
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
First actions (field-minded)
- 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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UN 1558 — Arsenic HAZMAT 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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FAQ
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
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.