UN 1935 — Cyanide solution, n.o.s.
Placard: Toxic. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1935 is Cyanide solution, n.o.s., a highly toxic cyanide liquid assigned to ERG Guide 157. Acids can release hydrogen cyanide gas, so pH control, air monitoring and runoff containment are critical.
Hazard overview: UN 1935 presents cyanide poisoning, hydrogen cyanide gas, skin/ingestion exposure and contaminated-runoff hazards. Odor is not a reliable warning.
Response guidance: For a UN 1935 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and choose entry/fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1935 should emphasize hydrogen cyanide generation from acids, odor unreliability, air monitoring, decontamination, medical coordination and runoff control. Use ERG 157, SDS and local SOP.
Regulatory context: Cyanide solution, n.o.s. is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Cyanide solution, n.o.s. should be stored in tightly closed compatible containers in a secure toxic-material area away from acids, oxidizers, food/feed, heat and unauthorized access. Storage should include cyanide emergency planning and runoff control.
UN 1935 Quick Details
Common Hazards of UN 1935
- HIGHLY TOXIC cyanide solution; inhalation, ingestion or skin contact may be fatal.
- Acids or acidic runoff can release hydrogen cyanide gas, which is highly toxic and flammable.
- Odor is not a reliable warning for hydrogen cyanide exposure.
- Solution can contaminate clothing, tools, drains and waterways.
- Fire may produce hydrogen cyanide, nitrogen oxides and other toxic gases.
- Runoff and decontamination water may carry cyanide contamination.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Clear to pale yellow liquid with a faint bitter almond odor (though many people cannot detect this odor). Aqueous solution of various cyanide salts at room temperature.
| Also known as | Cyanide aqueous solutionHydrogen cyanide solutionAlkali cyanide solutionSodium cyanide solutionPotassium cyanide solution |
| Appearance | Clear to pale yellow liquid with a faint bitter almond odor (though many people cannot detect this odor). Aqueous solution of various cyanide salts at room temperature. |
| Flash Point | Not applicable (aqueous solution, non-flammable) |
| Boiling Point | Approximately 100C (212F), varies with concentration |
| Vapor Density | Not applicable (solution) |
| Water Reactivity | Already in aqueous solution; dilution may release hydrogen cyanide gas, especially if acidic |
Fireground Response Guidance — UN 1935
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing selected by hazmat specialists. Level A may be needed for close entry or unknown hydrogen cyanide vapor risk; avoid all skin contact.
Isolation & Evacuation
First Actions for a UN 1935 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, mist, smoke or gas and avoid skin or eye contact.
- Keep acids away from the solution and monitor for hydrogen cyanide where available; odor is not a reliable warning.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- 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 vapor, dust, fire involvement, gas accumulation 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 1935 — Cyanide solution, n.o.s.Use 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.