☣️ UN 2240 • CLASS 8
Chromosulphuric acid
Placard: Corrosive. 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 2240
Class: 8
Placard type: Corrosive
ERG: Guide 154 (check current ERG)
Isolation: ERG 154: isolate spill 25-50m all directions; for large spills consider initial evacuation 100m downwind; contain runoff to prevent environmental contamination
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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 2240 — Chromosulphuric acid HAZMAT 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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FAQ
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
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.