☣️ UN 1684 • CLASS 6
UN 1684 — Silver cyanide
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 1684 Quick Details
UN 1684
Product name: Silver cyanide
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: isolate spill area at least 25m in all directions; if large spill, isolate 100m; evacuate downwind areas if fire or decomposition occurs
Common Hazards of UN 1684
- 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 | Silver(I) cyanideCyanide of silverArgentous cyanideSilver monocyanide |
| CAS Number | 506-64-9 |
| Appearance | White to grayish-white odorless crystalline powder or solid. Darkens on exposure to light. Insoluble in water. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water, but releases toxic hydrogen cyanide gas when exposed to acids or heat |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1684
Extinguishing Media
Water spray, dry chemical, CO2, or foam may be used for surrounding fires; avoid creating dust
PPE Requirements
⚠️ Level A or B required; full encapsulation recommended; SCBA mandatory; avoid all skin contact; chemical-resistant gloves and suit essential
Isolation & Evacuation
ERG 151: isolate spill area at least 25m in all directions; if large spill, isolate 100m; evacuate downwind areas if fire or decomposition occurs
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 1684 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 1684 — Silver cyanideHAZMAT RADIO NOTE — UN 1684
Product: Silver cyanide
Class 6 / Toxic / ERG 151
PPE: Level A or B required; full encapsulation recommended; SCBA mandatory; avoid all skin contact; chemical-resistant gloves and suit essential
ISOLATION: ERG 151: isolate spill area at least 25m in all directions; if large spill, isolate 100m; evacuate downwind areas if fire or decomposition occurs
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 1684 — Silver cyanide
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: White to grayish-white odorless crystalline powder or solid. Darkens on exposure to light. Insoluble in water.
Water Reactivity: No significant reaction with water, but releases toxic hydrogen cyanide gas when exposed to acids or heat
Extinguishing: Water spray, dry chemical, CO2, or foam may be used for surrounding fires; avoid creating dust
PPE: Level A or B required; full encapsulation recommended; SCBA mandatory; avoid all skin contact; chemical-resistant gloves and suit essential
Isolation: ERG 151: isolate spill area at least 25m in all directions; if large spill, isolate 100m; evacuate downwind areas if fire or decomposition occurs
— 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/1684 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1684 Silver cyanide Cls6 ERG151 | ERG 151: isolate spill area at least 25m in all directions; if large spill, isol | allfirefighter.com/hazmat/un/1684SMS / 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/1684
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Frequently Asked Questions about UN 1684
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 A or B required; full encapsulation recommended; SCBA mandatory; avoid all skin contact; chemical-resistant gloves and suit essential
Water reactivity: No significant reaction with water, but releases toxic hydrogen cyanide gas when exposed to acids or heat. Recommended extinguishing: Water spray, dry chemical, CO2, or foam may be used for surrounding fires; avoid creating dust.
ERG Guide 151 recommendation: ERG 151: isolate spill area at least 25m in all directions; if large spill, isolate 100m; evacuate downwind areas if fire or decomposition occurs
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.