UN 2659 — Sodium chloroacetate
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2659 is Sodium chloroacetate, a toxic chloroacetate salt assigned to ERG Guide 151. Dust, toxic solution and HCl fire products require control.
Hazard overview: TOXIC chloroacetate salt; inhalation, ingestion or skin contact may cause severe injury. Dissolves in water to form toxic solution; no violent water reaction is expected. Dust or solution can irritate or burn eyes, skin and respiratory tissue.
Response guidance: For UN 2659, isolate the area, avoid skin contact and use SCBA where dust, vapor, mist or fire is present. Prevent spread of contaminated runoff, cool containers from protection and verify controls with SDS and ERG 151.
Firefighter training notes: Training for UN 2659 should emphasize toxic exposure routes, skin absorption, SCBA use, dust/vapor control, decontamination, runoff containment and SDS verification. Use ERG 151, SDS and local SOP.
Regulatory context: Sodium chloroacetate is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Sodium chloroacetate should be stored in tightly closed labeled containers in a secure toxic-material area with dust control, secondary containment, restricted access and SDS-based segregation.
UN 2659 Quick Details
Common Hazards of UN 2659
- TOXIC chloroacetate salt; inhalation, ingestion or skin contact may cause severe injury.
- Dissolves in water to form toxic solution; no violent water reaction is expected.
- Dust or solution can irritate or burn eyes, skin and respiratory tissue.
- Non-combustible solid, but heating or fire may produce hydrogen chloride and toxic decomposition products.
- Runoff may carry toxic chloroacetate contamination.
- Containers may rupture or fail when heated.
- Avoid dust generation and contaminated clothing exposure.
Chemical Identity & Physical Properties
White to tan crystalline powder or granular solid. Hygroscopic with slight acetic odor. Solid at room temperature.
| Also known as | Monochloroacetic acid sodium saltChloroacetic acid sodium saltSodium monochloroacetateMCA sodium salt |
| CAS Number | 3926-62-3 |
| Appearance | White to tan crystalline powder or granular solid. Hygroscopic with slight acetic odor. Solid at room temperature. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water, forms acidic solution. No violent reaction but releases heat on dissolution. |
Fireground Response Guidance — UN 2659
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, vapor, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing.
Isolation & Evacuation
First Actions for a UN 2659 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated dust, liquid, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 151, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2659 — Sodium chloroacetateUse 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.