UN 1764 — Dichloroacetic acid
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1764 is Dichloroacetic acid, a toxic corrosive halogenated acid assigned to ERG Guide 153. It can burn skin and eyes and may produce HCl-containing toxic gases in fire.
Hazard overview: UN 1764 presents corrosive acid, toxic vapor and contaminated-runoff hazards. It is generally not highly flammable, but fire or heating can generate toxic/corrosive decomposition gases.
Response guidance: For a UN 1764 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 153. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1764 should emphasize corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 153, SDS and local SOP.
Regulatory context: Dichloroacetic acid is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, pesticide/waste handling where applicable, 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: Dichloroacetic acid should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated hazardous-material area according to SDS and local procedures.
UN 1764 Quick Details
Common Hazards of UN 1764
- TOXIC and CORROSIVE halogenated acid; inhalation, ingestion or skin contact may cause severe injury.
- Liquid can burn eyes, skin and respiratory tissue.
- Combustible material: may burn under fire conditions.
- Fire may produce hydrogen chloride and other toxic/corrosive gases.
- Runoff may carry acidic toxic contamination.
- Containers may rupture or fail when heated.
- Vapors may be heavier than air and collect in low areas.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a pungent, acrid odor. Corrosive liquid at room temperature.
| Also known as | DCABichloroacetic acidDichloroethanoic acidAcid dichloroacetique |
| CAS Number | 79-43-6 |
| Appearance | Colorless to pale yellow liquid with a pungent, acrid odor. Corrosive liquid at room temperature. |
| Flash Point | Not available (non-flammable corrosive) |
| Boiling Point | 194C (381F) |
| Vapor Density | 4.45 (heavier than air) |
| Water Reactivity | Soluble in water, forms corrosive acidic solution but no violent reaction |
Fireground Response Guidance — UN 1764
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, dust, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS.
Isolation & Evacuation
First Actions for a UN 1764 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 or spray and avoid skin or eye contact.
- 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, water reaction or unknown concentration is present.
- Use ERG Guide 153, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1764 — Dichloroacetic acidUse 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.