UN 2661 — Hexachloroacetone
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2661 is Hexachloroacetone, a toxic chlorinated ketone assigned to ERG Guide 153. Heavy vapor and toxic chlorinated fire products are key hazards.
Hazard overview: TOXIC chlorinated ketone; inhalation, ingestion or skin contact may cause severe injury. Solid may melt near ambient conditions, creating molten contact and vapor exposure hazards. Vapors are much heavier than air and may collect in low or confined areas.
Response guidance: For UN 2661, isolate the area, avoid skin contact and use SCBA where dust, vapor, mist or fire is present. Control ignition or moisture hazards as applicable and contain toxic/corrosive runoff.
Firefighter training notes: Training for UN 2661 should emphasize toxic exposure routes, SCBA use, dust/vapor monitoring, fire behavior, decontamination, runoff containment and SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Hexachloroacetone 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: Hexachloroacetone should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 2661 Quick Details
Common Hazards of UN 2661
- TOXIC chlorinated ketone; inhalation, ingestion or skin contact may cause severe injury.
- Solid may melt near ambient conditions, creating molten contact and vapor exposure hazards.
- Vapors are much heavier than air and may collect in low or confined areas.
- Combustible material: may burn but does not ignite readily.
- Hydrolysis or fire may produce hydrogen chloride, phosgene-type gases and other toxic/corrosive fumes.
- Runoff may be toxic, corrosive and environmentally harmful.
- Avoid all skin contact and prevent spread of contaminated residues.
Chemical Identity & Physical Properties
Colorless to pale yellow crystalline solid or liquid above 4°C (39°F). Pungent, irritating odor. May be encountered as molten material.
| Also known as | Hexachloro-2-propanoneHexachloropropanone1,1,1,3,3,3-HexachloroacetonePerchloroacetone |
| CAS Number | 116-16-5 |
| Appearance | Colorless to pale yellow crystalline solid or liquid above 4°C (39°F). Pungent, irritating odor. May be encountered as molten material. |
| Flash Point | Not applicable (non-flammable) |
| Boiling Point | 203°C (397°F) with decomposition |
| Vapor Density | 9.2 (much heavier than air) |
| Water Reactivity | Slowly hydrolyzes in water forming corrosive products; avoid prolonged water contact |
Fireground Response Guidance — UN 2661
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and full chemical protective clothing. Level A may be needed for heavy vapor, splash risk or unknown concentrations; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2661 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 liquid, dust, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 153, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2661 — HexachloroacetoneUse 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.