UN 1717 — Acetyl chloride
Placard: Flammable. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1717 is Acetyl chloride, a highly flammable corrosive acid chloride assigned to ERG Guide 155. It reacts violently with water and moist air, releasing heat and corrosive hydrogen chloride fumes.
Hazard overview: UN 1717 presents flammable vapor, flashback, corrosive fume and water-reactivity hazards. Keep water away from product and control ignition sources, sewers and low areas.
Response guidance: For a UN 1717 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 155. 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 1717 should emphasize water-reactive corrosive fumes, dry-agent selection, vapor control, ignition control where relevant, runoff containment and decontamination. Use ERG 155, SDS and local SOP.
Regulatory context: Acetyl 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: Acetyl 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 1717 Quick Details
Common Hazards of UN 1717
- HIGHLY FLAMMABLE and CORROSIVE liquid; vapors may ignite easily and flash back.
- Reacts violently with water or moist air, releasing heat and corrosive hydrogen chloride/acetic acid fumes.
- Vapors form explosive mixtures with air, including in sewers and confined spaces.
- Vapors are heavier than air and may spread along the ground to ignition sources.
- Liquid and fumes can burn eyes, skin and respiratory tissue.
- Containers may rupture or explode when heated or contaminated with water.
- Runoff may be corrosive and flammable/toxic contamination.
Chemical Identity & Physical Properties
Colorless to slightly yellow fuming liquid with a pungent, irritating odor. Fumes in moist air due to reaction with water vapor.
| Also known as | Ethanoyl chlorideAcetic acid chlorideAcetic chloride |
| CAS Number | 75-36-5 |
| Appearance | Colorless to slightly yellow fuming liquid with a pungent, irritating odor. Fumes in moist air due to reaction with water vapor. |
| Flash Point | 4C (40F) |
| Boiling Point | 51C (124F) |
| Vapor Density | 2.7 (heavier than air) |
| Water Reactivity | Reacts violently with water producing heat, corrosive acetic acid and HCl fumes. Do not use water directly on material. |
Fireground Response Guidance — UN 1717
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 1717 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.
- Eliminate ignition sources if it is safe to do so and keep vapors out of drains, sewers and low areas.
- 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 155, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1717 — Acetyl 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.