☣️ UN 2661 • CLASS 6
UN 2661 — Hexachloroacetone
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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UN 2661 Quick Details
UN 2661
Product name: Hexachloroacetone
DOT Class: 6
Placard type: Toxic
ERG Guide: 153 (check current ERG)
Initial isolation: ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation 800m
Common Hazards of UN 2661
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Combustible material: may burn but does not ignite readily.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
Chemical Identity & Physical Properties
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2661
Extinguishing Media
Dry chemical, CO2, water spray for cooling; foam may be used for vapor suppression
PPE Requirements
⚠️ Level A recommended due to extreme toxicity; SCBA and full chemical-resistant suit required; avoid all skin/eye contact with molten or solid material
Isolation & Evacuation
ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation 800m
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 153).
First Actions for a UN 2661 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 2661 — HexachloroacetoneHAZMAT RADIO NOTE — UN 2661
Product: Hexachloroacetone
Class 6 / Toxic / ERG 153
PPE: Level A recommended due to extreme toxicity; SCBA and full chemical-resistant suit required; avoid all skin/eye contact with molten or solid material
ISOLATION: ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation 800m
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 2661 — Hexachloroacetone
Class: 6 | Placard: Toxic | ERG Guide: 153
Appearance: Colorless to pale yellow crystalline solid or liquid above 4°C (39°F). Pungent, irritating odor. May be encountered as molten material.
Water Reactivity: Slowly hydrolyzes in water forming corrosive products; avoid prolonged water contact
Extinguishing: Dry chemical, CO2, water spray for cooling; foam may be used for vapor suppression
PPE: Level A recommended due to extreme toxicity; SCBA and full chemical-resistant suit required; avoid all skin/eye contact with molten or solid material
Isolation: ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation 800m
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
• Contact with molten substance may cause severe burns to skin and eyes.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/2661 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2661 Hexachloroacetone Cls6 ERG153 | ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail ca | allfirefighter.com/hazmat/un/2661SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/2661
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Frequently Asked Questions about UN 2661
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears). Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level A recommended due to extreme toxicity; SCBA and full chemical-resistant suit required; avoid all skin/eye contact with molten or solid material
Water reactivity: Slowly hydrolyzes in water forming corrosive products; avoid prolonged water contact. Recommended extinguishing: Dry chemical, CO2, water spray for cooling; foam may be used for vapor suppression.
ERG Guide 153 recommendation: ERG 153: isolate spill/leak area at least 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider initial evacuation 800m
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 153 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.