☣️ UN 1639 • CLASS 6
UN 1639 — Mercury nucleate
Placard: Toxic. ERG Guide 151. 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 1639 Quick Details
UN 1639
Product name: Mercury nucleate
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: Isolate spill area immediately for at least 25-50 meters in all directions; increase isolation distance for large spills; evacuate area if fire involves material
Common Hazards of UN 1639
- Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
- 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
- Containers may explode when heated.
- Runoff may pollute waterways.
Chemical Identity & Physical Properties
| Also known as | Mercury nucleateNucleated mercuryMercury nucleate complexOrganomercury nucleate compound |
| Appearance | Appearance and physical state vary depending on specific nucleate formulation; typically solid or powder form at room temperature. Color may range from white to yellowish. Organomercury compounds often have characteristic odors. |
| Flash Point | Not applicable (inorganic/organometallic compound, not typically flammable) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid form under normal conditions) |
| Water Reactivity | No significant violent reaction with water, but may slowly hydrolyze or dissolve releasing toxic mercury species |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1639
Extinguishing Media
Dry chemical, CO2, water spray for cooling (material itself is non-combustible but may be involved in fire)
PPE Requirements
⚠️ Level B minimum required; SCBA mandatory; chemical-resistant suit, gloves, and boots essential to prevent any skin contact with highly toxic mercury compound
Isolation & Evacuation
ERG 151: Isolate spill area immediately for at least 25-50 meters in all directions; increase isolation distance for large spills; evacuate area if fire involves material
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 1639 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.
- 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 1639 — Mercury nucleateHAZMAT RADIO NOTE — UN 1639
Product: Mercury nucleate
Class 6 / Toxic / ERG 151
PPE: Level B minimum required; SCBA mandatory; chemical-resistant suit, gloves, and boots essential to prevent any skin contact with highly toxic mercury compound
ISOLATION: ERG 151: Isolate spill area immediately for at least 25-50 meters in all directions; increase isolation distance for large spills; evacuate area if fire involves 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 1639 — Mercury nucleate
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: Appearance and physical state vary depending on specific nucleate formulation; typically solid or powder form at room temperature. Color may range from white to yellowish. Organomercury compounds often have characteristic odors.
Water Reactivity: No significant violent reaction with water, but may slowly hydrolyze or dissolve releasing toxic mercury species
Extinguishing: Dry chemical, CO2, water spray for cooling (material itself is non-combustible but may be involved in fire)
PPE: Level B minimum required; SCBA mandatory; chemical-resistant suit, gloves, and boots essential to prevent any skin contact with highly toxic mercury compound
Isolation: ERG 151: Isolate spill area immediately for at least 25-50 meters in all directions; increase isolation distance for large spills; evacuate area if fire involves material
— Key Hazards —
• Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
• Avoid any skin contact.
• Fire may produce irritating, corrosive and/or toxic gases.
— 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.
• 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/1639 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1639 Mercury nucleate Cls6 ERG151 | ERG 151: Isolate spill area immediately for at least 25-50 meters in all directi | allfirefighter.com/hazmat/un/1639SMS / 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/1639
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Frequently Asked Questions about UN 1639
Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. 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 Containers may explode when heated. Runoff may pollute waterways.
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 required; SCBA mandatory; chemical-resistant suit, gloves, and boots essential to prevent any skin contact with highly toxic mercury compound
Water reactivity: No significant violent reaction with water, but may slowly hydrolyze or dissolve releasing toxic mercury species. Recommended extinguishing: Dry chemical, CO2, water spray for cooling (material itself is non-combustible but may be involved in fire).
ERG Guide 151 recommendation: ERG 151: Isolate spill area immediately for at least 25-50 meters in all directions; increase isolation distance for large spills; evacuate area if fire involves material
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 151 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.