☣️ UN 2529 • CLASS 3
Isobutyric acid
Placard: Flammable. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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Quick details
UN 2529
Class: 3
Placard type: Flammable
ERG: Guide 132 (check current ERG)
Isolation: ERG 132: isolate spill/leak area 50m in all directions; for large spill isolate 800m downwind
Chemical & Response Details
| Also known as | 2-Methylpropanoic acidIsopropylformic acidDimethylacetic acid2-Methylpropionic acid |
| CAS Number | 79-31-2 |
| Appearance | Colorless liquid with a pungent, rancid butter-like odor. Corrosive organic acid that is miscible with water and most organic solvents. |
| Flash Point | 56°C (132°F) |
| Boiling Point | 154°C (309°F) |
| Vapor Density | 3.0 (heavier than air) |
| Water Reactivity | Miscible with water; no violent reaction but solution is corrosive |
| Extinguishing | Alcohol-resistant foam, CO2, dry chemical; water spray for cooling |
| PPE | ⚠️ Level B minimum; SCBA required in enclosed spaces; chemical-resistant gloves and suit due to corrosivity |
| Isolation | ERG 132: isolate spill/leak area 50m in all directions; for large spill isolate 800m downwind |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Flammable/combustible material.
- May be ignited by heat, sparks or flames.
- Vapors may form explosive mixtures with air.
- Vapors may travel to source of ignition and flash back.
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapor explosion hazard indoors, outdoors or in sewers.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Runoff to sewer may create fire or explosion hazard.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 50 meters (150 feet) in all directions.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 2529 — Isobutyric acid HAZMAT RADIO NOTE — UN 2529
Product: Isobutyric acid
Class 3 / Flammable / ERG 132
PPE: Level B minimum; SCBA required in enclosed spaces; chemical-resistant gloves and suit due to corrosivity
ISOLATION: ERG 132: isolate spill/leak area 50m in all directions; for large spill isolate 800m downwind
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 2529 — Isobutyric acid
Class: 3 | Placard: Flammable | ERG Guide: 132
Appearance: Colorless liquid with a pungent, rancid butter-like odor. Corrosive organic acid that is miscible with water and most organic solvents.
Water Reactivity: Miscible with water; no violent reaction but solution is corrosive
Extinguishing: Alcohol-resistant foam, CO2, dry chemical; water spray for cooling
PPE: Level B minimum; SCBA required in enclosed spaces; chemical-resistant gloves and suit due to corrosivity
Isolation: ERG 132: isolate spill/leak area 50m in all directions; for large spill isolate 800m downwind
— Key Hazards —
• Flammable/combustible material.
• May be ignited by heat, sparks or flames.
• Vapors may form explosive mixtures with air.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/2529 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2529 Isobutyric acid Cls3 ERG132 | ERG 132: isolate spill/leak area 50m in all directions; for large spill isolate | allfirefighter.com/hazmat/un/2529SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/2529
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FAQ
Flammable/combustible material. May be ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum; SCBA required in enclosed spaces; chemical-resistant gloves and suit due to corrosivity
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 132 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.