☣️ UN 1624 • CLASS 6
UN 1624 — Mercuric chloride
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.
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UN 1624 Quick Details
UN 1624
Product name: Mercuric chloride
DOT Class: 6
Placard type: Toxic
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and consider evacuation 1600m downwind
Common Hazards of UN 1624
- 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
| Also known as | Mercury(II) chlorideMercury bichlorideCorrosive sublimateBichloride of mercury |
| CAS Number | 7487-94-7 |
| Appearance | White crystalline solid or powder. Odorless. Soluble in water forming a corrosive solution. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | 304C (579F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Dissolves in water forming corrosive acidic solution; no violent reaction |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1624
Extinguishing Media
Water spray, CO2, dry chemical (material is non-combustible but may be involved in fire)
PPE Requirements
⚠️ Level A or B with full face SCBA; impervious suit, gloves, boots; avoid all skin contact with solid or solution
Isolation & Evacuation
ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and consider evacuation 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).
First Actions for a UN 1624 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.
- 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 1624 — Mercuric chlorideHAZMAT RADIO NOTE — UN 1624
Product: Mercuric chloride
Class 6 / Toxic / ERG 154
PPE: Level A or B with full face SCBA; impervious suit, gloves, boots; avoid all skin contact with solid or solution
ISOLATION: ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and consider evacuation 1600m 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 1624 — Mercuric chloride
Class: 6 | Placard: Toxic | ERG Guide: 154
Appearance: White crystalline solid or powder. Odorless. Soluble in water forming a corrosive solution.
Water Reactivity: Dissolves in water forming corrosive acidic solution; no violent reaction
Extinguishing: Water spray, CO2, dry chemical (material is non-combustible but may be involved in fire)
PPE: Level A or B with full face SCBA; impervious suit, gloves, boots; avoid all skin contact with solid or solution
Isolation: ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and consider evacuation 1600m 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 —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1624 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1624 Mercuric chloride Cls6 ERG154 | ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and | allfirefighter.com/hazmat/un/1624SMS / 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/1624
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Frequently Asked Questions about UN 1624
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.
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 or B with full face SCBA; impervious suit, gloves, boots; avoid all skin contact with solid or solution
Water reactivity: Dissolves in water forming corrosive acidic solution; no violent reaction. Recommended extinguishing: Water spray, CO2, dry chemical (material is non-combustible but may be involved in fire).
ERG Guide 154 recommendation: ERG 154: isolate spill 25m all directions; if involved in fire, isolate 800m and consider evacuation 1600m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 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.