☣️ UN 1627 • CLASS 6
UN 1627 — Mercurous nitrate
Placard: Toxic. ERG Guide 141. 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 1627 Quick Details
UN 1627
Product name: Mercurous nitrate
DOT Class: 6
Placard type: Toxic
ERG Guide: 141 (check current ERG)
Initial isolation: ERG 141: isolate spill area immediate 25m in all directions; for large spill increase initial isolation to 50m; if tank/railcar involved in fire isolate 800m in all directions
Common Hazards of UN 1627
- These substances will accelerate burning when involved in a fire.
- May explode from heat or contamination.
- Some may burn rapidly.
- Some will react explosively with hydrocarbons (fuels).
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- Toxic by ingestion.
Chemical Identity & Physical Properties
| Also known as | Mercury(I) nitrateMercurous nitrate dihydrateNitric acid mercury(I) saltMercuric nitrate |
| CAS Number | 10415-75-5 |
| Appearance | White to grayish-white crystalline solid or powder. Odorless. Decomposes upon exposure to light, turning gray or black. |
| Flash Point | Not applicable (non-combustible oxidizing solid) |
| Boiling Point | Not applicable (decomposes before boiling at approximately 70C) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water with slow decomposition; no violent reaction but may form acidic solution |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1627
Extinguishing Media
Water spray to control fire, CO2, dry chemical; avoid organic materials which may react with oxidizer
PPE Requirements
⚠️ Level B minimum with full face respirator; mercury compound requires impervious protective clothing and SCBA for fire or spill response
Isolation & Evacuation
ERG 141: isolate spill area immediate 25m in all directions; for large spill increase initial isolation to 50m; if tank/railcar involved in fire isolate 800m in all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 141).
First Actions for a UN 1627 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
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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📋 Copy & Share Field Card
UN 1627 — Mercurous nitrateHAZMAT RADIO NOTE — UN 1627
Product: Mercurous nitrate
Class 6 / Toxic / ERG 141
PPE: Level B minimum with full face respirator; mercury compound requires impervious protective clothing and SCBA for fire or spill response
ISOLATION: ERG 141: isolate spill area immediate 25m in all directions; for large spill increase initial isolation to 50m; if tank/railcar involved in fire isolate 800m in all directions
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 1627 — Mercurous nitrate
Class: 6 | Placard: Toxic | ERG Guide: 141
Appearance: White to grayish-white crystalline solid or powder. Odorless. Decomposes upon exposure to light, turning gray or black.
Water Reactivity: Soluble in water with slow decomposition; no violent reaction but may form acidic solution
Extinguishing: Water spray to control fire, CO2, dry chemical; avoid organic materials which may react with oxidizer
PPE: Level B minimum with full face respirator; mercury compound requires impervious protective clothing and SCBA for fire or spill response
Isolation: ERG 141: isolate spill area immediate 25m in all directions; for large spill increase initial isolation to 50m; if tank/railcar involved in fire isolate 800m in all directions
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• May explode from heat or contamination.
• Some may burn rapidly.
— 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/1627 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1627 Mercurous nitrate Cls6 ERG141 | ERG 141: isolate spill area immediate 25m in all directions; for large spill inc | allfirefighter.com/hazmat/un/1627SMS / 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/1627
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Frequently Asked Questions about UN 1627
These substances will accelerate burning when involved in a fire. May explode from heat or contamination. Some may burn rapidly. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard. Toxic by ingestion.
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 B minimum with full face respirator; mercury compound requires impervious protective clothing and SCBA for fire or spill response
Water reactivity: Soluble in water with slow decomposition; no violent reaction but may form acidic solution. Recommended extinguishing: Water spray to control fire, CO2, dry chemical; avoid organic materials which may react with oxidizer.
ERG Guide 141 recommendation: ERG 141: isolate spill area immediate 25m in all directions; for large spill increase initial isolation to 50m; if tank/railcar involved in fire isolate 800m in all directions
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 141 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.