☣️ UN 2525 • CLASS 6
Ethyl oxalate
Placard: Toxic. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 2525
Class: 6
Placard type: Toxic
ERG: Guide 156 (check current ERG)
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
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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
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 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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UN 2525 — Ethyl oxalate HAZMAT 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 —
• 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/2525 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
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. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/2525
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FAQ
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
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 and chemical-resistant suit recommended; avoid skin contact as oxalic acid products are corrosive
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 156 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.