UN 1463 — Chromium trioxide, anhydrous
Placard: Oxidizer. ERG Guide 141. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1463 is Chromium trioxide, anhydrous, a Class 5 oxidizer assigned to ERG Guide 141. It combines oxidizer fire behavior with toxic, corrosive chromium(VI) dust and acidic solution concerns.
Hazard overview: UN 1463 presents oxidizer, corrosive chromium(VI) exposure and contamination hazards. Dust, smoke and runoff should be controlled because chromium trioxide can form chromic acid with water and is hazardous even without fire.
Response guidance: For a UN 1463 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 141. Establish incident command, isolate the area, stay upwind, keep fuels and organics away, avoid contaminated absorbents and choose extinguishing or spill-control actions based on ERG, SDS and local SOP.
Firefighter training notes: Training for UN 1463 should emphasize oxidizer fire behavior plus toxic metal contamination control, dust avoidance, PPE selection, decontamination and runoff containment. Use ERG 141, SDS and local SOP.
Regulatory context: Chromium trioxide, anhydrous is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Chromium trioxide, anhydrous should be stored in compatible oxidizer storage away from fuels, organics, reducing agents, heat and contamination. Keep containers closed and dry, and manage dust/runoff controls because toxic metal contamination may create additional regulatory and cleanup concerns.
UN 1463 Quick Details
Common Hazards of UN 1463
- OXIDIZER: may intensify fire and accelerate burning of combustible materials.
- May ignite combustibles such as wood, paper, oil, clothing, packaging or contaminated absorbents.
- Chromium(VI) oxidizers may react dangerously with organics, fuels and reducing agents.
- Containers may rupture or explode when heated.
- Fire may produce irritating and/or toxic gases.
- Runoff may spread oxidizing material and create fire, explosion or environmental hazards.
- Dust, solution or decomposition products may irritate or injure eyes, skin or respiratory tissue.
- Chromium(VI) dust, smoke and runoff may present serious toxic, corrosive and carcinogenic exposure concerns.
Chemical Identity & Physical Properties
Dark purplish-red to brownish-red, odorless crystalline solid that is highly deliquescent (absorbs moisture from air).
| Also known as | Chromic acid anhydrideChromium(VI) oxideChromic anhydrideChromium oxide |
| CAS Number | 1333-82-0 |
| Appearance | Dark purplish-red to brownish-red, odorless crystalline solid that is highly deliquescent (absorbs moisture from air). |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | Decomposes at 250C (482F) before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Dissolves readily in water forming chromic acid solution; reaction is exothermic and may generate heat |
Fireground Response Guidance — UN 1463
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, dust, decomposition or confined-space exposure. Wear chemical-resistant protective clothing, gloves and eye/face protection; avoid chromium(VI) dust, acidic solution and contaminated runoff.
Isolation & Evacuation
First Actions for a UN 1463 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.
- Keep combustibles, fuels, organics, reducing agents and contaminated materials away from the spill.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust clouds and prevent runoff from contacting combustibles, drains or incompatible materials when possible.
- Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
- Isolate the spill or fire area and expand the perimeter if large quantities, contamination, heating or container involvement are present.
- Use ERG Guide 141, shipping papers, SDS and local SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1463 — Chromium trioxide, anhydrousUse 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.