UN 2395 — Isobutyryl chloride
Placard: Flammable. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2395 is Isobutyryl chloride, a flammable corrosive acid chloride assigned to ERG Guide 155. Moisture can release hydrogen chloride fumes and heat.
Hazard overview: FLAMMABLE and CORROSIVE acid chloride liquid; vapors may ignite and cause severe irritation or burns. Reacts strongly with water or moist air, releasing hydrogen chloride fumes and heat. Vapors are heavier than air and may travel to ignition sources and flash back.
Response guidance: For UN 2395, isolate the area, remove ignition sources and use SCBA. Control water use because moisture can release HCl fumes; contain acidic runoff and confirm tactics with SDS and ERG 155.
Firefighter training notes: Training for UN 2395 should emphasize acid chloride moisture reaction, HCl fuming, flammable vapor control, acid-resistant PPE, runoff containment and decontamination. Use ERG 155, SDS and local SOP.
Regulatory context: Isobutyryl chloride 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: Isobutyryl chloride should be stored in tightly closed compatible containers in a cool, dry, ventilated flammable/corrosive area away from moisture, heat, ignition sources, oxidizers and bases. Provide secondary containment.
UN 2395 Quick Details
Common Hazards of UN 2395
- FLAMMABLE and CORROSIVE acid chloride liquid; vapors may ignite and cause severe irritation or burns.
- Reacts strongly with water or moist air, releasing hydrogen chloride fumes and heat.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Liquid contact can burn eyes, skin and respiratory tissue.
- Fire may produce hydrogen chloride, carbon monoxide and other toxic/corrosive gases.
- Runoff may be acidic, corrosive 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, acrid odor. Fumes in moist air due to reaction with water vapor.
| Also known as | 2-Methylpropanoyl chlorideDimethylacetyl chlorideIsobutyric acid chloride2-Methyl-1-propanoyl chloride |
| CAS Number | 79-30-1 |
| Appearance | Colorless to pale yellow liquid with a pungent, acrid odor. Fumes in moist air due to reaction with water vapor. |
| Flash Point | -12°C (10°F) |
| Boiling Point | 92°C (198°F) |
| Vapor Density | 3.6 (heavier than air) |
| Water Reactivity | Reacts violently with water, generating heat and hydrochloric acid fumes. Do not use water directly on material. |
Fireground Response Guidance — UN 2395
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2395 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; keep responders out of low vapor areas.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, mist or smoke and avoid skin or eye contact.
- Keep water contact controlled because moisture can intensify hydrogen chloride fuming.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 155, SDS, shipping papers and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2395 — Isobutyryl 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.