UN 2744 — Cyclobutyl chloroformate
Placard: Toxic. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2744 is Cyclobutyl chloroformate, a toxic flammable chloroformate assigned to ERG Guide 155. Water reaction, HCl fuming and flashback are key concerns.
Hazard overview: HIGHLY FLAMMABLE and TOXIC chloroformate liquid; vapors may ignite easily and form explosive mixtures with air. Reacts with water or moist air, releasing hydrogen chloride, carbon dioxide and heat. Vapors are heavier than air and may travel to ignition sources and flash back.
Response guidance: For UN 2744, isolate the spill, stay upwind and use SCBA with chemical protection. Control moisture contact, use compatible dry agents and contain acidic/toxic runoff under SDS and ERG 155.
Firefighter training notes: Training for UN 2744 should emphasize moisture-reactive corrosive fuming, dry-agent choice, SCBA/Level A decisions, decontamination and acidic runoff control. Use ERG 155, SDS and local SOP.
Regulatory context: Cyclobutyl chloroformate 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: Cyclobutyl chloroformate should be stored dry in tightly closed compatible containers away from water, moisture, bases, alcohols, amines, heat and unauthorized access. Provide secondary containment.
UN 2744 Quick Details
Common Hazards of UN 2744
- HIGHLY FLAMMABLE and TOXIC chloroformate liquid; vapors may ignite easily and form explosive mixtures with air.
- Reacts with water or moist air, releasing hydrogen chloride, carbon dioxide and heat.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Liquid and vapor can burn eyes, skin and respiratory tissue.
- Fire may produce hydrogen chloride, phosgene-type gases and other toxic/corrosive smoke.
- Runoff may be acidic, toxic and flammable-contaminated.
- Containers may rupture or explode when heated or contaminated with water.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a pungent, irritating odor. Liquid at room temperature.
| Also known as | Cyclobutyl chlorocarbonateChloroformic acid cyclobutyl esterCarbonochloridic acid cyclobutyl ester |
| CAS Number | 13747-48-1 |
| Appearance | Colorless to pale yellow liquid with a pungent, irritating odor. Liquid at room temperature. |
| Flash Point | Below 23C (73F) |
| Boiling Point | Approximately 138-142C (280-288F) |
| Vapor Density | 4.7 (heavier than air) |
| Water Reactivity | Reacts with water releasing HCl gas and heat; avoid contact with moisture |
Fireground Response Guidance — UN 2744
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing. Level A may be needed for heavy vapor, fuming, splash risk or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 2744 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.
- Eliminate ignition sources if this can be done safely.
- Keep water or moisture contact controlled because it can release heat and corrosive gases.
- 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 155, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2744 — Cyclobutyl chloroformateUse 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.