UN 2576 — Phosphorus oxybromide, molten
Placard: Corrosive. ERG Guide 137. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Phosphorus oxybromide, molten is a fuming corrosive phosphorus halide. The key hazards are moisture reaction, corrosive vapor and severe burn injury from hot material.
Hazard overview: Moisture contact can generate hydrogen bromide and acidic runoff while adding heat to the release. Because the material is molten, responders must also consider splash, thermal burns and vapor exposure in low areas.
Response guidance: Keep water away from the product unless specialist guidance directs otherwise. Isolate the area, use dry-compatible control methods where appropriate and cool uninvolved exposed containers from a protected position without directing streams into the material.
Firefighter training notes: Training should cover water-reactive corrosive behavior, molten splash hazards and acid-gas monitoring. Entry teams need to understand dry-control options and protected cooling tactics.
Regulatory context: UN 2576 is listed as Phosphorus oxybromide, molten, Class 8 corrosive. Verify temperature, package type and any moisture-reactive precautions on the shipping papers.
Storage & handling: Keep containers dry, tightly closed and protected from moisture. Separate from bases, alcohols, water sources, oxidizers and incompatible metals.
UN 2576 Quick Details
Common Hazards of UN 2576
- Molten corrosive material; contact can cause severe thermal and chemical burns.
- Reacts with water or moist air to release corrosive hydrogen bromide fumes and heat.
- Heavy corrosive vapors may collect in low or poorly ventilated areas.
- Fire or decomposition can produce toxic bromine- and phosphorus-containing gases.
- Water applied directly to the material can increase fuming, spattering and runoff hazards.
- Containers may rupture when heated or contaminated with moisture.
- Acidic runoff can corrode metals and injure responders.
Chemical Identity & Physical Properties
When cool, phosphorus oxybromide is a colorless to pale yellow crystalline solid; in this entry it is transported as molten material. It fumes in moist air and has a pungent irritating odor.
| Also known as | Phosphoryl bromidePOBr3Phosphoric tribromide oxidePhosphorus tribromide oxide |
| CAS Number | 7789-59-5 |
| Appearance | Colorless to pale yellow crystalline solid when cool; presented here as a molten liquid. Pungent, irritating odor. Fumes heavily in moist air. |
| Flash Point | Not applicable (non-flammable corrosive) |
| Boiling Point | 191.7C (377F) |
| Vapor Density | 6.8 (much heavier than air) |
| Water Reactivity | Reacts violently with water, producing corrosive hydrogen bromide and phosphoric acid vapors. Do not use water directly on material. |
Fireground Response Guidance — UN 2576
Extinguishing Media
PPE Requirements
Level A protection is appropriate for unknown or active releases. SCBA, full encapsulation and acid-compatible gloves and boots are needed where corrosive vapor or splash is possible.
Isolation & Evacuation
First Actions for a UN 2576 Incident
- Call 911 and the emergency response number shown on shipping papers; confirm the material with ERG, SDS and container markings.
- Keep unauthorized personnel away and establish hot, warm and cold zones before entry.
- Stay upwind, uphill and upstream; avoid low areas where vapors, dust or runoff may collect.
- Avoid breathing vapors, dust, mist or decomposition products and prevent skin or eye contact.
- Do not touch damaged packages or containers unless properly trained and wearing suitable chemical PPE.
- Ventilate confined spaces only after atmospheric monitoring and only with trained, equipped personnel.
- Use ERG Guide 137, SDS, shipping papers and monitoring results for isolation, PPE and fire-control decisions.
📋 Copy & Share Field Card
UN 2576 — Phosphorus oxybromide, moltenUse 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.