☣️ UN 1631 • CLASS 6

UN 1631 — Mercury benzoate

Placard: Toxic. ERG Guide 154. 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 1631 is Mercury benzoate, a toxic mercury compound assigned to ERG Guide 154. It may form corrosive or toxic solutions, and fire can produce persistent mercury contamination.

Hazard overview: UN 1631 presents toxic mercury exposure, dust/solution contact and contaminated-runoff hazards. Some salts are corrosive in solution, and heating may produce toxic mercury or halogen-containing fumes.

Response guidance: For a UN 1631 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 154. 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 1631 should emphasize mercury salt toxicity, dust or solution contamination, SCBA use, runoff containment, decontamination and waste-control coordination. Use ERG 154, SDS and local SOP.

Regulatory context: Mercury benzoate is regulated as a toxic mercury hazardous material. Transportation, occupational exposure, spill reporting, waste handling, storage and environmental controls may vary by compound, 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: Mercury benzoate 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, solution leaks and mercury-contaminated runoff.

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UN 1631 Quick Details

UN 1631
Product name: Mercury benzoate
DOT Class: 6
Placard type: Toxic
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: isolate spill area immediate 25m in all directions; if fire or large spill, isolate 800m in all directions and evacuate downwind

Common Hazards of UN 1631

  • TOXIC and potentially corrosive mercury compound; inhalation, ingestion or skin contact may cause severe injury.
  • Dust, solution or contaminated residue can be hazardous by skin contact, ingestion or inhalation.
  • Some mercury salts form corrosive or acidic solutions in water.
  • Fire or heating may produce toxic mercury fumes and corrosive halogen or organic decomposition products.
  • Runoff may spread persistent toxic mercury contamination.
  • Containers may rupture or fail when heated.
  • Avoid all unnecessary contact with solid, solution, dust and contaminated equipment.

Chemical Identity & Physical Properties

White to slightly yellowish crystalline powder or solid at room temperature. Odorless or faint benzoic acid odor.

Also known asMercuric benzoateMercury(II) benzoateBenzoic acid mercury saltMercury dibenzoate
CAS Number583-15-3
AppearanceWhite to slightly yellowish crystalline powder or solid at room temperature. Odorless or faint benzoic acid odor.
Flash PointNot applicable (non-flammable solid)
Boiling PointDecomposes before boiling
Vapor DensityNot applicable (solid)
Water ReactivitySlightly soluble in water with no significant violent reaction, but releases toxic mercury compounds
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1631

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 B minimum with SCBA and chemical-resistant suit; avoid all skin contact due to severe toxicity and corrosive properties

Use positive-pressure SCBA for dust, vapor, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; prevent skin contact and mercury-contaminated dust or runoff spread.

Isolation & Evacuation

ERG 154: isolate spill area immediate 25m in all directions; if fire or large spill, isolate 800m in all directions and evacuate downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).

First Actions for a UN 1631 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 or spreading contaminated powder, solution, runoff or debris.
  • 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 dust, vapor, fire involvement or unknown concentration is present.
  • Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

UN 1631 — Mercury benzoate
HAZMAT RADIO NOTE — UN 1631 Product: Mercury benzoate Class 6 / Toxic / ERG 154 PPE: Level B minimum with SCBA and chemical-resistant suit; avoid all skin contact due to severe toxicity and corrosive properties ISOLATION: ERG 154: isolate spill area immediate 25m in all directions; if fire or large spill, isolate 800m in all directions and evacuate 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 1631 — Mercury benzoate Class: 6 | Placard: Toxic | ERG Guide: 154 Appearance: White to slightly yellowish crystalline powder or solid at room temperature. Odorless or faint benzoic acid odor. Water Reactivity: Slightly soluble in water with no significant violent reaction, but releases toxic mercury compounds 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 B minimum with SCBA and chemical-resistant suit; avoid all skin contact due to severe toxicity and corrosive properties Isolation: ERG 154: isolate spill area immediate 25m in all directions; if fire or large spill, isolate 800m in all directions and evacuate downwind — Key Hazards — • TOXIC and potentially corrosive mercury compound; inhalation, ingestion or skin contact may cause severe injury. • Dust, solution or contaminated residue can be hazardous by skin contact, ingestion or inhalation. • Some mercury salts form corrosive or acidic solutions in water. — 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/mercury-benzoate-un-1631 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.

SMS (short)
UN1631 Mercury benzoate Cls6 ERG154 | allfirefighter.com/hazmat/un/mercury-benzoate-un-1631SMS / 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/mercury-benzoate-un-1631

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 1631

UN 1631 is Mercury benzoate, a hazardous material assigned to ERG Guide 154.

No. It is generally not flammable, but heating or fire can produce toxic and corrosive decomposition products.

ERG Guide 154 applies to UN 1631 for initial isolation, protective actions and first response guidance.

UN 1631 presents toxic mercury exposure, dust/solution contact and contaminated-runoff hazards. Some salts are corrosive in solution, and heating may produce toxic mercury or halogen-containing fumes.

Use positive-pressure SCBA for dust, vapor, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; prevent skin contact and mercury-contaminated dust or runoff spread.
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.