UN 1751 — Chloroacetic acid, solid
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1751 is Chloroacetic acid, solid, a toxic corrosive acid assigned to ERG Guide 153. It can cause severe burns and systemic poisoning through skin contact.
Hazard overview: UN 1751 presents toxic skin absorption, corrosive burn, combustible solid/liquid and acidic runoff hazards. Contaminated clothing and molten material can extend exposure.
Response guidance: For a UN 1751 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 1751 should emphasize toxic/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: Chloroacetic acid, solid 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 concentration, formulation, 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: Chloroacetic acid, solid 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 1751 Quick Details
Common Hazards of UN 1751
- TOXIC and CORROSIVE chloroacetic acid; inhalation, ingestion or skin contact may cause severe injury.
- Skin absorption can be significant and contaminated clothing may continue exposure.
- Solid or molten material 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.
Chemical Identity & Physical Properties
Colorless to light brown crystalline solid with a pungent, acetic acid-like odor. Deliquescent (absorbs moisture from air).
| Also known as | Monochloroacetic acidMCAChloroethanoic acid2-Chloroacetic acid |
| CAS Number | 79-11-8 |
| Appearance | Colorless to light brown crystalline solid with a pungent, acetic acid-like odor. Deliquescent (absorbs moisture from air). |
| Flash Point | 126C (259F) |
| Boiling Point | 189C (372F) |
| Vapor Density | 3.3 (heavier than air) |
| Water Reactivity | Soluble in water forming a corrosive solution; exothermic dissolution |
Fireground Response Guidance — UN 1751
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fume, dust, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS; Level A may be needed for close entry or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 1751 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 gas 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, gas, 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 1751 — Chloroacetic acid, solidUse 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.