☣️ 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.
Mercury benzoate is a highly toxic and corrosive substance that requires immediate attention in case of a spill or exposure. It is essential to follow proper emergency response procedures to minimize harm.
Hazard overview: Mercury benzoate can cause severe burns to skin and eyes upon contact with molten substance, and inhalation, ingestion, or skin contact with material may cause severe injury.
Response guidance: In case of a spill, isolate the area immediately and evacuate downwind. Use dry chemical, CO2, or water spray for cooling, and avoid dispersing the material.
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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/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- 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
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
Chemical Identity & Physical Properties
Mercury benzoate is a white to slightly yellowish crystalline powder or solid at room temperature, with an odorless or faint benzoic acid odor.
| Also known as | Mercuric benzoateMercury(II) benzoateBenzoic acid mercury saltMercury dibenzoate |
| CAS Number | 583-15-3 |
| Appearance | White to slightly yellowish crystalline powder or solid at room temperature. Odorless or faint benzoic acid odor. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Slightly 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
Dry chemical, CO2, water spray for cooling; avoid dispersing material
PPE Requirements
⚠️ Level B minimum with SCBA and chemical-resistant suit; avoid all skin contact due to severe toxicity and corrosive properties
Use Level B minimum PPE with SCBA and a chemical-resistant suit to avoid all skin contact due to severe toxicity and corrosive properties.
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
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- 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 1631 — Mercury benzoateHAZMAT 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.
=== 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: Dry chemical, CO2, water spray for cooling; avoid dispersing material
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/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
• 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/mercury-benzoate-un-1631 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
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
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Frequently Asked Questions about UN 1631
No, UN 1631 Mercury benzoate is not flammable.
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.