UN 2820 — Butyric acid
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2820 is Butyric acid, a corrosive organic acid assigned to ERG Guide 153. Burns, acidic runoff and combustible fire behavior require control.
Hazard overview: CORROSIVE organic acid; liquid, dust or vapor can burn eyes, skin and respiratory tissue. Combustible material: may burn but does not ignite readily. Water contact forms acidic solution; dilution can spread corrosive contamination.
Response guidance: For UN 2820, isolate the area, avoid skin contact and use SCBA where dust, vapor, mist or fire is present. Contain corrosive/toxic runoff and verify controls with SDS and ERG 153.
Firefighter training notes: Training for UN 2820 should emphasize exposure routes, SCBA use, vapor/dust monitoring, fire behavior, decontamination, runoff containment and SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Butyric acid 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: Butyric acid should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 2820 Quick Details
Common Hazards of UN 2820
- CORROSIVE organic acid; liquid, dust or vapor can burn eyes, skin and respiratory tissue.
- Combustible material: may burn but does not ignite readily.
- Water contact forms acidic solution; dilution can spread corrosive contamination.
- Heated vapors may collect in low or confined areas and may ignite under fire conditions.
- Fire may produce carbon monoxide and irritating acidic 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 oily liquid with a strong, rancid butter or vomit-like odor. Corrosive liquid at room temperature.
| Also known as | n-Butyric acidButanoic acidEthylacetic acidPropylformic acid1-Propanecarboxylic acid |
| CAS Number | 107-92-6 |
| Appearance | Colorless to pale yellow oily liquid with a strong, rancid butter or vomit-like odor. Corrosive liquid at room temperature. |
| Flash Point | 72°C (162°F) |
| Boiling Point | 163°C (325°F) |
| Vapor Density | 3.0 (heavier than air) |
| Water Reactivity | Miscible with water; no violent reaction but generates heat on mixing |
Fireground Response Guidance — UN 2820
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, dust, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing.
Isolation & Evacuation
First Actions for a UN 2820 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 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 2820 — Butyric acidUse 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.