UN 3472 — Crotonic acid, liquid
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3472 is Crotonic acid, liquid, a corrosive combustible organic acid assigned to ERG Guide 153. Heavy vapors, burns and acidic runoff require control.
Hazard overview: CORROSIVE combustible organic acid liquid; contact can burn eyes, skin and respiratory tissue. Combustible liquid; heated vapors may form ignitable mixtures with air. Vapors are heavier than air and may collect in low or confined areas.
Response guidance: For UN 3472, isolate the area, avoid skin contact and use SCBA where vapor, dust, mist or fire is present. Contain runoff and verify controls with SDS/ERG 153.
Firefighter training notes: Training for UN 3472 should emphasize exposure routes, SCBA use, vapor/dust monitoring, decontamination, runoff containment and SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Crotonic acid, liquid is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, concentration, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Crotonic acid, liquid should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 3472 Quick Details
Common Hazards of UN 3472
- CORROSIVE combustible organic acid liquid; contact can burn eyes, skin and respiratory tissue.
- Combustible liquid; heated vapors may form ignitable mixtures with air.
- Vapors are heavier than air and may collect in low or confined areas.
- Can irritate skin, eyes and respiratory tract; concentrated contact may cause burns.
- Fire may produce carbon monoxide and irritating organic acid smoke.
- Runoff may be acidic, corrosive and harmful to waterways.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid or crystalline solid (melts near room temperature at 72°C). Has a pungent, irritating odor.
| Also known as | trans-2-Butenoic acidβ-Methylacrylic acidtrans-Crotonic acid2-Butenoic acid |
| CAS Number | 3724-65-0 |
| Appearance | Colorless to pale yellow liquid or crystalline solid (melts near room temperature at 72°C). Has a pungent, irritating odor. |
| Flash Point | 88°C (190°F) |
| Boiling Point | 185°C (365°F) |
| Vapor Density | 3.0 (heavier than air) |
| Water Reactivity | Soluble in water; no violent reaction but solution is corrosive |
Fireground Response Guidance — UN 3472
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, fire or confined-space exposure. Wear chemical-resistant splash suit, gloves, boots and eye/face protection.
Isolation & Evacuation
First Actions for a UN 3472 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.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers, equipment 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 153, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3472 — Crotonic acid, liquidUse 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.