UN 2232 — Chloroacetaldehyde
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2232 is Chloroacetaldehyde, a toxic corrosive chlorinated aldehyde assigned to ERG Guide 153. It may polymerize or decompose if contaminated, heated or stored improperly.
Hazard overview: TOXIC and CORROSIVE chlorinated aldehyde liquid; inhalation, ingestion or skin contact may cause severe injury. Vapors are irritating and may injure eyes, skin and respiratory tissue. May polymerize or decompose during storage, especially if contaminated or heated.
Response guidance: For a UN 2232 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 153. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff, dust or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2232 should emphasize toxic skin/dust/vapor exposure, contaminated clothing, toxic fire products, decontamination waste and runoff containment. Use ERG 153, SDS and local SOP.
Regulatory context: Chloroacetaldehyde is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Chloroacetaldehyde should be stored in tightly closed compatible containers in a secure toxic-material area with secondary containment, restricted access, ventilation and waste/decontamination planning according to SDS.
UN 2232 Quick Details
Common Hazards of UN 2232
- TOXIC and CORROSIVE chlorinated aldehyde liquid; inhalation, ingestion or skin contact may cause severe injury.
- Vapors are irritating and may injure eyes, skin and respiratory tissue.
- May polymerize or decompose during storage, especially if contaminated or heated.
- Combustible material: may burn but does not ignite readily.
- Fire may produce hydrogen chloride, carbon monoxide and other toxic/corrosive gases.
- Runoff may carry toxic chlorinated contamination.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Colorless to yellow liquid with a pungent, acrid odor. Highly reactive and corrosive. May polymerize or decompose on storage.
| Also known as | 2-ChloroacetaldehydeChloroethanalMonochloroacetaldehyde2-Chloroethanal |
| CAS Number | 107-20-0 |
| Appearance | Colorless to yellow liquid with a pungent, acrid odor. Highly reactive and corrosive. May polymerize or decompose on storage. |
| Flash Point | 88°C (190°F) |
| Boiling Point | 85-90°C (185-194°F) |
| Vapor Density | 2.7 (heavier than air) |
| Water Reactivity | Soluble in water; reacts slowly with water to form hydrochloric acid and other products |
Fireground Response Guidance — UN 2232
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 selected from SDS; avoid all skin contact.
Isolation & Evacuation
First Actions for a UN 2232 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, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and wearing appropriate protective equipment.
- Prevent contaminated dust, liquid, residues, runoff and decontamination waste from spreading.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, dust generation, water reaction or unknown product identity.
- Use ERG Guide 153, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2232 — ChloroacetaldehydeUse 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.