☣️ UN 2525 • CLASS 6
UN 2525 — Ethyl oxalate
Placard: Toxic. 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.
Ethyl oxalate is a toxic and combustible liquid used in various industrial applications. It has a mild, fruity ester odor and is a colorless to pale yellow oily liquid at room temperature.
Hazard overview: Ethyl oxalate is a combustible material that may burn but does not ignite readily. It will react with water, releasing flammable, toxic, or corrosive gases and runoff.
Response guidance: In case of fire, use alcohol-resistant foam, CO2, dry chemical, or water spray for cooling containers. For spills, isolate the area and evacuate if a tank or rail car is involved in a fire.
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UN 2525 Quick Details
UN 2525
Product name: Ethyl oxalate
DOT Class: 6
Placard type: Toxic
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: isolate spill or leak area immediately for at least 25-50 meters in all directions; if tank/rail car involved in fire, isolate 800 meters in all directions
Common Hazards of UN 2525
- Combustible material: may burn but does not ignite readily.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapors may travel to source of ignition and flash back.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
- TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
Chemical Identity & Physical Properties
Ethyl oxalate is a colorless to pale yellow oily liquid with a mild, fruity ester odor and is liquid at room temperature with relatively low volatility.
| Also known as | Diethyl oxalateOxalic acid diethyl esterEthanedioic acid diethyl esterDEO |
| CAS Number | 95-92-1 |
| Appearance | Colorless to pale yellow oily liquid with a mild, fruity ester odor. Liquid at room temperature with relatively low volatility. |
| Flash Point | 76°C (168°F) |
| Boiling Point | 185-186°C (365-367°F) |
| Vapor Density | 4.1 (heavier than air) |
| Water Reactivity | Reacts slowly with water producing ethanol and oxalic acid; reaction accelerates with heat and moisture |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2525
Extinguishing Media
Alcohol-resistant foam, CO2, dry chemical, water spray for cooling containers
PPE Requirements
⚠️ Level B minimum; SCBA and chemical-resistant suit recommended; avoid skin contact as oxalic acid products are corrosive
Wear Level B minimum personal protective equipment, including SCBA and chemical-resistant suit, and avoid skin contact as oxalic acid products are corrosive.
Isolation & Evacuation
ERG 156: isolate spill or leak area immediately for at least 25-50 meters in all directions; if tank/rail car involved in fire, isolate 800 meters in all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).
First Actions for a UN 2525 Incident
- 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 in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- 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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📋 Copy & Share Field Card
UN 2525 — Ethyl oxalateHAZMAT RADIO NOTE — UN 2525
Product: Ethyl oxalate
Class 6 / Toxic / ERG 156
PPE: Level B minimum; SCBA and chemical-resistant suit recommended; avoid skin contact as oxalic acid products are corrosive
ISOLATION: ERG 156: isolate spill or leak area immediately for at least 25-50 meters in all directions; if tank/rail car involved in fire, isolate 800 meters in all directions
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 2525 — Ethyl oxalate
Class: 6 | Placard: Toxic | ERG Guide: 156
Appearance: Colorless to pale yellow oily liquid with a mild, fruity ester odor. Liquid at room temperature with relatively low volatility.
Water Reactivity: Reacts slowly with water producing ethanol and oxalic acid; reaction accelerates with heat and moisture
Extinguishing: Alcohol-resistant foam, CO2, dry chemical, water spray for cooling containers
PPE: Level B minimum; SCBA and chemical-resistant suit recommended; avoid skin contact as oxalic acid products are corrosive
Isolation: ERG 156: isolate spill or leak area immediately for at least 25-50 meters in all directions; if tank/rail car involved in fire, isolate 800 meters in all directions
— Key Hazards —
• Combustible material: may burn but does not ignite readily.
• Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
• When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
— First Actions —
• 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 in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/2525 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN2525 Ethyl oxalate Cls6 ERG156 | ERG 156: isolate spill or leak area immediately for at least 25-50 meters in all | allfirefighter.com/hazmat/un/2525SMS / 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/ethyl-oxalate-un-2525
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Frequently Asked Questions about UN 2525
Yes, UN 2525 ethyl oxalate is a combustible material that may burn but does not ignite readily.
UN 2525 reacts slowly with water to produce ethanol and oxalic acid, and the reaction accelerates with heat and moisture.
Wear Level B minimum personal protective equipment, including SCBA and chemical-resistant suit, and avoid skin contact as oxalic acid products are corrosive.
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.