UN 2933 — Methyl 2-chloropropionate
Placard: Flammable. ERG Guide 129. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Methyl 2-chloropropionate is a flammable chlorinated ester assigned to ERG 129. The response focus is vapor ignition control, downwind vapor awareness and protection from liquid or vapor exposure.
Hazard overview: Methyl 2-chloropropionate vapors can form explosive mixtures with air and travel along the ground to ignition sources. Burning or decomposition can generate irritating and toxic acidic gases, so smoke exposure should be avoided.
Response guidance: Isolate the area, remove ignition sources, stop the leak only if it can be done safely and keep runoff out of sewers. Use alcohol-resistant foam, dry chemical or CO2 for fire control and water spray for container cooling from a distance.
Firefighter training notes: Train crews on flammable liquid vapor control, sewer protection, foam application and container cooling. Vapor monitoring and ignition source control should occur before entry when conditions allow.
Regulatory context: Methyl 2-chloropropionate is transported as a hazardous material under its UN entry and ERG 129. Verify packing group, concentration and emergency contact on shipping papers.
Storage & handling: Store in tightly closed containers in a cool, ventilated flammable-liquids area. Keep away from heat, sparks, oxidizers, strong bases and incompatible reactive chemicals.
UN 2933 Quick Details
Common Hazards of UN 2933
- Methyl 2-chloropropionate is a flammable liquid; vapors can ignite from heat, sparks or flames.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Vapor explosion hazard exists indoors, outdoors, in sewers and confined spaces.
- Liquid or vapor contact may irritate or injure skin, eyes and respiratory tract.
- Fire may produce hydrogen chloride, phosgene-like decomposition products and other toxic gases.
- Runoff to drains may create fire, explosion or contamination hazards.
- Containers may rupture when heated.
Chemical Identity & Physical Properties
Methyl 2-chloropropionate is a liquid ester. Color and odor may vary by purity, but vapors should be treated as heavier-than-air and potentially irritating.
| Also known as | Methyl alpha-chloropropionateMethyl 2-chloropropanoate2-Chloropropionic acid methyl esterPropionic acid, 2-chloro-, methyl ester |
| CAS Number | 17639-93-9 |
| Appearance | Colorless to pale yellow liquid with a pungent, fruity ester odor. Liquid at room temperature. |
| Flash Point | 49°C (120°F) |
| Boiling Point | 132-134°C (270-273°F) |
| Vapor Density | 4.3 (heavier than air) |
| Water Reactivity | No violent water reaction expected, but water may spread liquid and contaminated runoff |
Fireground Response Guidance — UN 2933
Extinguishing Media
PPE Requirements
Use structural firefighting gear and SCBA for fire. For spill entry, use chemical-resistant clothing, gloves and eye protection suitable for organic ester liquids.
Isolation & Evacuation
First Actions for a UN 2933 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and eliminate ignition sources.
- Stay upwind, uphill and upstream; keep out of low areas.
- Avoid breathing vapors and avoid skin or eye contact.
- Do not touch damaged containers or spilled liquid without proper PPE.
- Ventilate confined spaces only if trained, equipped and authorized.
- Use ERG 129, SDS, shipping papers and air monitoring for final decisions.
📋 Copy & Share Field Card
UN 2933 — Methyl 2-chloropropionateUse 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.