UN 1688 — Sodium cacodylate
Placard: Toxic. ERG Guide 152. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1688 is Sodium cacodylate, a toxic hazardous material assigned to ERG Guide 152. Responders should verify the exact product with shipping papers, package markings and SDS before close action.
Hazard overview: UN 1688 presents toxic exposure hazards by inhalation, ingestion or skin contact. Fire, decomposition or runoff may produce toxic contamination and require air monitoring, isolation and decontamination.
Response guidance: For a UN 1688 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 152. 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 1688 should emphasize toxic exposure routes, air monitoring, PPE selection, decontamination and preventing contaminated runoff. Use ERG 152, SDS and local SOP.
Regulatory context: Sodium cacodylate 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: Sodium cacodylate should be stored in tightly closed compatible containers in a secure toxic-material area according to SDS and local hazardous materials procedures.
UN 1688 Quick Details
Common Hazards of UN 1688
- TOXIC material; may be harmful or fatal if inhaled, ingested or absorbed through skin.
- Avoid breathing vapors, dust or mist and avoid skin or eye contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may carry toxic contamination and may pollute waterways.
- Containers may rupture or fail when heated.
- Specific toxicity and absorption risk should be confirmed from shipping papers and SDS.
Chemical Identity & Physical Properties
White to off-white crystalline powder or solid. Odorless or slight characteristic odor. Hygroscopic, absorbs moisture from air.
| Also known as | Sodium dimethylarsinateDimethylarsinic acid sodium saltCacodylic acid sodium saltHydroxydimethylarsine oxide sodium salt |
| CAS Number | 124-65-2 |
| Appearance | White to off-white crystalline powder or solid. Odorless or slight characteristic odor. Hygroscopic, absorbs moisture from air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water with no violent reaction; aqueous solutions are weakly alkaline |
Fireground Response Guidance — UN 1688
Extinguishing Media
PPE Requirements
Use protective equipment selected from SDS, monitoring results and incident command.
Isolation & Evacuation
First Actions for a UN 1688 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.
- 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.
- 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 152, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1688 — Sodium cacodylateUse 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.