UN 1627 — Mercurous nitrate
Placard: Toxic. ERG Guide 141. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Mercurous nitrate is a toxic substance that can accelerate burning when involved in a fire. It may also explode from heat or contamination.
Hazard overview: These substances will accelerate burning when involved in a fire. May explode from heat or contamination.
Response guidance: Use water spray to control fire, CO2, dry chemical. Avoid organic materials which may react with oxidizer.
UN 1627 Quick Details
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
White to grayish-white crystalline solid or powder. Odorless. Decomposes upon exposure to light, turning gray or black.
| 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 |
Fireground Response Guidance — UN 1627
Extinguishing Media
PPE Requirements
Level B minimum with full face respirator; mercury compound requires impervious protective clothing and SCBA for fire or spill response
Isolation & Evacuation
First Actions for a UN 1627 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
- Consider initial downwind evacuation for at least 100 meters (330 feet).
📋 Copy & Share Field Card
UN 1627 — Mercurous nitrateUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.