UN 1729 — Anisoyl chloride
Placard: Corrosive. ERG Guide 156. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1729 is Anisoyl chloride, a combustible corrosive acid chloride assigned to ERG Guide 156. Water or moist air can release corrosive hydrogen chloride fumes.
Hazard overview: UN 1729 presents corrosive fume, combustible liquid and water-reactivity hazards. Use dry compatible control methods and prevent runoff from spreading corrosive contamination.
Response guidance: For a UN 1729 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 156. 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 1729 should emphasize water-reactive corrosive fumes, dry-agent selection, vapor control, ignition control where relevant, runoff containment and decontamination. Use ERG 156, SDS and local SOP.
Regulatory context: Anisoyl chloride 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: Anisoyl chloride should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers, ignition sources where relevant and unauthorized access. Protect containers from corrosion, leakage and contamination.
UN 1729 Quick Details
Common Hazards of UN 1729
- CORROSIVE combustible acid chloride; may burn but does not ignite readily.
- Reacts with water or moist air to release corrosive hydrogen chloride fumes.
- Vapors may be heavier than air and collect in low or confined areas.
- Liquid and fumes can burn eyes, skin and respiratory tissue.
- Fire may produce irritating, corrosive and/or toxic gases.
- Containers may rupture or fail when heated or contaminated with water.
- Runoff may spread corrosive and toxic contamination.
Chemical Identity & Physical Properties
Clear to pale yellow liquid with a pungent, acrid odor. Corrosive and moisture-sensitive.
| Also known as | p-Methoxybenzoyl chloride4-Methoxybenzoyl chloridep-Anisoyl chlorideAnisic acid chloride |
| CAS Number | 100-07-2 |
| Appearance | Clear to pale yellow liquid with a pungent, acrid odor. Corrosive and moisture-sensitive. |
| Flash Point | 118°C (244°F) |
| Boiling Point | 262°C (504°F) |
| Vapor Density | Approximately 5.9 (heavier than air) |
| Water Reactivity | Reacts with water releasing corrosive and toxic HCl gas; avoid direct water contact |
Fireground Response Guidance — UN 1729
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fume, 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 1729 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 or mist and avoid skin or eye contact.
- Keep water and moisture away from the released product unless incident command confirms a compatible cooling or control use.
- 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, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 156, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1729 — Anisoyl chlorideUse 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.