☣️ 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.

UN 1558 is Arsenic, a toxic arsenic material assigned to ERG Guide 152. The key responder concern is preventing inhalation of dust or fumes and preventing contaminated runoff.

Hazard overview: UN 1558 presents arsenic dust, fume and ingestion hazards. Heating or fire can create toxic arsenic oxide fumes, and dry powder can contaminate clothing, equipment and surfaces.

Response guidance: For a UN 1558 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 152. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.

Firefighter training notes: Training for UN 1558 should emphasize arsenic dust/fume exposure, contamination control, SCBA use, runoff containment and decontamination. Common errors include treating nonflammable toxic solids as low risk and spreading dust during cleanup. Use ERG 152, SDS and local SOP.

Regulatory context: Arsenic is regulated as a toxic arsenic hazardous material. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by compound, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.

Storage & handling: Arsenic should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated toxic-material area away from food, incompatible chemicals, heat and unauthorized access. Prevent dust release, leaks and contaminated runoff.

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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 arsenic material; may be fatal if inhaled, ingested or absorbed through skin.
  • Dust or powder can create a serious inhalation and contamination hazard.
  • Avoid skin contact and prevent dust from becoming airborne.
  • Fire or heating may produce toxic arsenic oxide fumes.
  • Runoff from fire control or spill control may pollute waterways.
  • Containers may rupture or fail when heated.
  • Specific toxicity and solubility depend on the exact arsenic compound.

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 asMetallic arsenicArsenic metalGrey arsenicElemental arsenic
CAS Number7440-38-2
AppearanceSteel-grey or tin-white, odorless, brittle crystalline solid at room temperature. May appear as a black or yellow powder depending on form.
Flash PointNot applicable (non-combustible solid)
Boiling Point613C (1135F) - sublimes without melting
Vapor DensityNot applicable (solid)
Water ReactivityNo 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

Use extinguishing agents appropriate for the surrounding fire and SDS. Water spray may cool containers or reduce dust only when runoff can be controlled as toxic contamination.

PPE Requirements

⚠️ Level A required for spill response; full-face SCBA, chemical-resistant suit; highly toxic by all routes of exposure

Use positive-pressure SCBA for dust, mist, fumes, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; avoid all skin contact and contaminated dust.

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 the emergency response telephone number on the shipping paper, if available.
  • Keep unauthorized personnel away.
  • Stay upwind, uphill and/or upstream.
  • Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact.
  • Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
  • Avoid creating dust clouds; cover or contain dry material only using methods directed by SDS and incident command.
  • Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
  • Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement or unknown concentration is present.
  • Use ERG Guide 152, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

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.

SMS WhatsApp
=== 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: Use extinguishing agents appropriate for the surrounding fire and SDS. Water spray may cool containers or reduce dust only when runoff can be controlled as toxic contamination. 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 arsenic material; may be fatal if inhaled, ingested or absorbed through skin. • Dust or powder can create a serious inhalation and contamination hazard. • Avoid skin contact and prevent dust from becoming airborne. — First Actions — • CALL 911. Then call the emergency response telephone number on the shipping paper, if available. • Keep unauthorized personnel away. • Stay upwind, uphill and/or upstream. • Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact. 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.

SMS (short)
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

Related UN Numbers in Class 6

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1558

UN 1558 is Arsenic, a toxic hazardous material assigned to ERG Guide 152.

No. It is generally not flammable, but fire or heating can produce toxic arsenic fumes.

ERG Guide 152 applies to UN 1558 for initial isolation, protective actions and first response guidance.

UN 1558 presents arsenic dust, fume and ingestion hazards. Heating or fire can create toxic arsenic oxide fumes, and dry powder can contaminate clothing, equipment and surfaces.

Use positive-pressure SCBA for dust, mist, fumes, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; avoid all skin contact and contaminated dust.

Arsenic dust or fumes can contaminate clothing, equipment and surfaces and may be dangerous by inhalation or ingestion.
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.