☣️ UN 2240 • CLASS 8
UN 2240 — Chromosulphuric acid
Placard: Corrosive. ERG Guide 154. 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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UN 2240 Quick Details
UN 2240
Product name: Chromosulphuric acid
DOT Class: 8
Placard type: Corrosive
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
Common Hazards of UN 2240
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
Chemical Identity & Physical Properties
| Also known as | Sulfochromic acidChromic sulfuric acidChromium trioxide-sulfuric acid mixtureChrome-sulfuric acid cleaning solution |
| CAS Number | 7783-08-6 |
| Appearance | Dark red to brown viscous liquid with a pungent, acrid odor. Highly corrosive oxidizing solution consisting of chromium trioxide dissolved in sulfuric acid. |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | Approximately 338C (640F) - decomposes before boiling |
| Vapor Density | Not applicable (low volatility liquid) |
| Water Reactivity | Reacts exothermically with water generating heat; dilute slowly with stirring to prevent violent boiling and splashing |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2240
Extinguishing Media
Dry chemical, CO2, dry sand; do not use water spray directly on liquid due to violent spattering
PPE Requirements
⚠️ Level A or B required; full-face SCBA, acid-resistant suit, butyl rubber gloves and boots; eye wash and safety shower immediately available
Isolation & Evacuation
ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).
First Actions for a UN 2240 Incident
- 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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📋 Copy & Share Field Card
UN 2240 — Chromosulphuric acidHAZMAT RADIO NOTE — UN 2240
Product: Chromosulphuric acid
Class 8 / Corrosive / ERG 154
PPE: Level A or B required; full-face SCBA, acid-resistant suit, butyl rubber gloves and boots; eye wash and safety shower immediately available
ISOLATION: ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
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 2240 — Chromosulphuric acid
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: Dark red to brown viscous liquid with a pungent, acrid odor. Highly corrosive oxidizing solution consisting of chromium trioxide dissolved in sulfuric acid.
Water Reactivity: Reacts exothermically with water generating heat; dilute slowly with stirring to prevent violent boiling and splashing
Extinguishing: Dry chemical, CO2, dry sand; do not use water spray directly on liquid due to violent spattering
PPE: Level A or B required; full-face SCBA, acid-resistant suit, butyl rubber gloves and boots; eye wash and safety shower immediately available
Isolation: ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— 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/2240 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2240 Chromosulphuric acid Cls8 ERG154 | ERG 154: isolate spill 25-50m all directions; for large spills consider initial | allfirefighter.com/hazmat/un/2240SMS / 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/2240
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Frequently Asked Questions about UN 2240
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas.
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 A or B required; full-face SCBA, acid-resistant suit, butyl rubber gloves and boots; eye wash and safety shower immediately available
Water reactivity: Reacts exothermically with water generating heat; dilute slowly with stirring to prevent violent boiling and splashing. Recommended extinguishing: Dry chemical, CO2, dry sand; do not use water spray directly on liquid due to violent spattering.
ERG Guide 154 recommendation: ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 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.