☣️ UN 2739 • CLASS 8
UN 2739 — Butyric anhydride
Placard: Corrosive. ERG Guide 156. 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.
Butyric anhydride is a combustible acid anhydride with corrosive vapor and liquid hazards. Water contact can generate heat and acidic runoff.
Hazard overview: The main hazards are corrosive contact, irritating vapor and combustible-liquid fire behavior. Water contact forms butyric acid and can increase heat, odor and corrosive runoff.
Response guidance: Isolate the spill, remove ignition sources and keep water out of the product. Use alcohol-resistant foam, dry chemical or CO2 for fire; cool closed containers with water spray from a protected position.
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UN 2739 Quick Details
UN 2739
Product name: Butyric anhydride
DOT Class: 8
Placard type: Corrosive
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: initially isolate 50m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Common Hazards of UN 2739
- Butyric anhydride is a combustible corrosive liquid.
- Contact can cause severe skin, eye and respiratory irritation or burns.
- Water reacts to form butyric acid and heat; large contacts may be vigorous.
- Vapors are heavier than air and may collect in low or confined areas.
- Heated vapors may form ignitable mixtures and flash back to an ignition source.
- Fire can produce irritating and corrosive smoke.
- Containers may rupture if heated or contaminated with water.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a strong, pungent, rancid butter-like odor. Oily consistency at room temperature
| Also known as | Butanoic anhydrideButanoic acid anhydriden-Butyric anhydrideButyric acid anhydride |
| CAS Number | 106-31-0 |
| Appearance | Colorless to pale yellow liquid with a strong, pungent, rancid butter-like odor. Oily consistency at room temperature. |
| Flash Point | 54°C (129°F) |
| Boiling Point | 198-200°C (388-392°F) |
| Vapor Density | 5.5 (heavier than air) |
| Water Reactivity | Reacts with water releasing heat and forming butyric acid. Reaction can be vigorous with large quantities. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2739
Extinguishing Media
Alcohol-resistant foam, CO2, dry chemical, water spray for cooling only
PPE Requirements
⚠️ Level B minimum with SCBA; chemical-resistant suit for spills; severe skin and eye irritant
Use SCBA with chemical-resistant clothing, gloves, boots and splash protection; avoid vapor inhalation and all skin or eye contact.
Isolation & Evacuation
ERG 156: initially isolate 50m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).
First Actions for a UN 2739 Incident
- Call 911 and the emergency response number shown on the shipping papers.
- Keep unauthorized personnel away and deny entry to the spill or fire area.
- Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
- Avoid breathing dust, vapor, mist or smoke; prevent skin and eye contact.
- Do not touch damaged containers or spilled material without appropriate PPE.
- Ventilate confined spaces only if personnel are trained, equipped and monitored.
- Use the ERG, SDS, shipping papers and air monitoring to set isolation, PPE and tactical decisions.
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📋 Copy & Share Field Card
UN 2739 — Butyric anhydrideHAZMAT RADIO NOTE — UN 2739
Product: Butyric anhydride
Class 8 / Corrosive / ERG 156
PPE: Level B minimum with SCBA; chemical-resistant suit for spills; severe skin and eye irritant
ISOLATION: ERG 156: initially isolate 50m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
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 2739 — Butyric anhydride
Class: 8 | Placard: Corrosive | ERG Guide: 156
Appearance: Colorless to pale yellow liquid with a strong, pungent, rancid butter-like odor. Oily consistency at room temperature.
Water Reactivity: Reacts with water releasing heat and forming butyric acid. Reaction can be vigorous with large quantities.
Extinguishing: Alcohol-resistant foam, CO2, dry chemical, water spray for cooling only
PPE: Level B minimum with SCBA; chemical-resistant suit for spills; severe skin and eye irritant
Isolation: ERG 156: initially isolate 50m in all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
— Key Hazards —
• Butyric anhydride is a combustible corrosive liquid.
• Contact can cause severe skin, eye and respiratory irritation or burns.
• Water reacts to form butyric acid and heat; large contacts may be vigorous.
— First Actions —
• Call 911 and the emergency response number shown on the shipping papers.
• Keep unauthorized personnel away and deny entry to the spill or fire area.
• Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
• Avoid breathing dust, vapor, mist or smoke; prevent skin and eye contact.
SOURCE: allfirefighter.com/hazmat/un/butyric-anhydride-un-2739 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN2739 Butyric anhydride Cls8 ERG156 | allfirefighter.com/hazmat/un/butyric-anhydride-un-2739SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/butyric-anhydride-un-2739
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Frequently Asked Questions about UN 2739
UN 2739 is Butyric anhydride, regulated as a hazardous material for transport and emergency response.
The main concern is a hazardous material behavior plus exposure risk from dust, vapor, liquid or fire products.
Approach from upwind, isolate the area, keep nonessential people out and verify the exact product with shipping papers or SDS.
Water reacts with the anhydride to form butyric acid and heat, so avoid direct streams on spilled product.
Use SCBA with chemical-resistant clothing, gloves, boots and splash protection; avoid vapor inhalation and all skin or eye contact.
Fire can produce irritating corrosive smoke and heated containers may rupture.
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.