UN 2240 — Chromosulphuric acid
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2240 is Chromosulphuric acid, a hazardous material assigned to ERG Guide 154. Verify exact hazards from shipping papers, markings and SDS.
Hazard overview: Hazards depend on the exact product, packaging and incident conditions. Verify the material using shipping papers, labels and SDS before close action. Fire may produce irritating or toxic smoke or gases.
Response guidance: For a UN 2240 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 154. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff, dust or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2240 should emphasize exposure routes, air monitoring, PPE selection, fire behavior, decontamination, runoff containment and ERG/SDS verification. Use ERG 154, SDS and local SOP.
Regulatory context: Chromosulphuric acid is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Chromosulphuric acid should be stored in compatible containers in a secure, cool, ventilated hazardous-material area according to SDS and local procedures.
UN 2240 Quick Details
Common Hazards of UN 2240
- Hazards depend on the exact product, packaging and incident conditions.
- Verify the material using shipping papers, labels and SDS before close action.
- Fire may produce irritating or toxic smoke or gases.
- Containers may fail or rupture when heated.
Chemical Identity & Physical Properties
Dark red to brown viscous liquid with a pungent, acrid odor. Highly corrosive oxidizing solution consisting of chromium trioxide dissolved in sulfuric acid.
| 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 |
Fireground Response Guidance — UN 2240
Extinguishing Media
PPE Requirements
Use protective equipment selected from SDS, monitoring results and incident command.
Isolation & Evacuation
First Actions for a UN 2240 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, dust generation, water reaction or unknown product identity.
- Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2240 — Chromosulphuric acidUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.