☣️ UN 1625 • CLASS 6
Mercuric nitrate
Placard: Toxic. 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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Quick details
UN 1625
Class: 6
Placard type: Toxic
ERG: Guide 141 (check current ERG)
Isolation: ERG 141: Isolate spill area at least 25m in all directions. For large spills isolate 50m. Evacuate immediate area if fire involves this material.
Chemical & Response Details
| Also known as | Mercury(II) nitrateMercury dinitrateMercuric nitrate monohydrateNitric acid mercury(II) salt |
| CAS Number | 10045-94-0 |
| Appearance | White to colorless crystalline solid or powder. Odorless. Hygroscopic and may appear moist. Highly toxic oxidizing agent. |
| Flash Point | Not applicable (non-combustible oxidizing solid) |
| Boiling Point | Decomposes at approximately 79C (174F) before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water forming acidic solution. No violent reaction but releases heat. |
| Extinguishing | Use water spray to cool containers. Dry chemical or CO2 for small fires. Avoid organic materials. |
| PPE | ⚠️ Level B minimum with SCBA. Full face respirator with mercury vapor cartridges. Neoprene or butyl rubber gloves. Prevent skin contact due to extreme toxicity. |
| Isolation | ERG 141: Isolate spill area at least 25m in all directions. For large spills isolate 50m. Evacuate immediate area if fire involves this material. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
First actions (field-minded)
- 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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UN 1625 — Mercuric nitrate HAZMAT RADIO NOTE — UN 1625
Product: Mercuric nitrate
Class 6 / Toxic / ERG 141
PPE: Level B minimum with SCBA. Full face respirator with mercury vapor cartridges. Neoprene or butyl rubber gloves. Prevent skin contact due to extreme toxicity.
ISOLATION: ERG 141: Isolate spill area at least 25m in all directions. For large spills isolate 50m. Evacuate immediate area if fire involves this material.
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 1625 — Mercuric nitrate
Class: 6 | Placard: Toxic | ERG Guide: 141
Appearance: White to colorless crystalline solid or powder. Odorless. Hygroscopic and may appear moist. Highly toxic oxidizing agent.
Water Reactivity: Soluble in water forming acidic solution. No violent reaction but releases heat.
Extinguishing: Use water spray to cool containers. Dry chemical or CO2 for small fires. Avoid organic materials.
PPE: Level B minimum with SCBA. Full face respirator with mercury vapor cartridges. Neoprene or butyl rubber gloves. Prevent skin contact due to extreme toxicity.
Isolation: ERG 141: Isolate spill area at least 25m in all directions. For large spills isolate 50m. Evacuate immediate area if fire involves this material.
— 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/1625 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1625 Mercuric nitrate Cls6 ERG141 | ERG 141: Isolate spill area at least 25m in all directions. For large spills iso | allfirefighter.com/hazmat/un/1625SMS / 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/1625
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FAQ
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 SCBA. Full face respirator with mercury vapor cartridges. Neoprene or butyl rubber gloves. Prevent skin contact due to extreme toxicity.
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.