UN 1679 — Potassium cuprocyanide
Placard: Toxic. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1679 is Potassium cuprocyanide, a highly toxic cyanide material assigned to ERG Guide 157. Acids, moisture or heat can release hydrogen cyanide, so air monitoring and runoff control are critical.
Hazard overview: UN 1679 presents cyanide poisoning, hydrogen cyanide gas and contaminated-runoff hazards. Avoid acid contact, control runoff, monitor for HCN where possible and do not rely on odor as a warning.
Response guidance: For a UN 1679 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1679 should emphasize hydrogen cyanide generation, acid/moisture incompatibility, air monitoring, SCBA use, decontamination and medical coordination. Use ERG 157, SDS and local SOP.
Regulatory context: Potassium cuprocyanide is regulated as a toxic cyanide hazardous material and may trigger strict exposure, spill reporting, waste and emergency planning controls. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Potassium cuprocyanide should be stored in tightly closed compatible containers in a secure, dry, well-ventilated toxic-material area away from acids, moisture contamination, oxidizers, heat and unauthorized access. Storage should include cyanide emergency planning and contaminated-runoff control appropriate to the SDS.
UN 1679 Quick Details
Common Hazards of UN 1679
- HIGHLY TOXIC cyanide material; inhalation, ingestion or skin contact may be fatal.
- Acids, moisture or heat may release hydrogen cyanide gas.
- Hydrogen cyanide can be flammable and rapidly dangerous in low or poorly ventilated areas.
- Fire may produce hydrogen cyanide, nitrogen oxides and other toxic gases.
- Runoff, absorbents and contaminated equipment may carry cyanide hazards.
- Containers may rupture or fail when heated.
- Odor is not a reliable warning for hydrogen cyanide exposure.
Chemical Identity & Physical Properties
White to pale yellow crystalline solid or powder. Odorless when dry, may release faint cyanide odor when exposed to moisture or acids.
| Also known as | Copper potassium cyanideCuprous potassium cyanidePotassium copper(I) cyanidePotassium dicyanocuprate(I) |
| CAS Number | 13682-73-0 |
| Appearance | White to pale yellow crystalline solid or powder. Odorless when dry, may release faint cyanide odor when exposed to moisture or acids. |
| Flash Point | Not applicable (inorganic salt) |
| Boiling Point | Not applicable (decomposes) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Slowly hydrolyzes in water releasing toxic hydrogen cyanide gas; reaction accelerates with heat or acids |
Fireground Response Guidance — UN 1679
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing selected by hazmat specialists for cyanide dust, solution, vapor or fire exposure. Level A may be needed for close entry or unknown hydrogen cyanide concentrations; decontamination should address cyanide and metal contamination.
Isolation & Evacuation
First Actions for a UN 1679 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact.
- Avoid acids, water contamination or incompatible cleanup materials contacting cyanide product unless incident command confirms a safe control method.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust clouds or spreading contaminated liquid, powder, solution, runoff or debris.
- Monitor for hydrogen cyanide where available; odor is not a reliable warning.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if dust, vapor, fire involvement or unknown concentration is present.
- Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1679 — Potassium cuprocyanideUse 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.