UN 2466 — Potassium superoxide
Placard: Oxidizer. ERG Guide 143. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2466 is Potassium superoxide, a reactive oxidizer assigned to ERG Guide 143. Water can release oxygen, heat and caustic potassium hydroxide.
Hazard overview: STRONG OXIDIZER and reactive peroxide/superoxide; may explode from friction, heat or contamination. Reacts violently with water, producing oxygen, heat and caustic potassium hydroxide. Can ignite combustibles and greatly intensify fire.
Response guidance: For UN 2466, isolate the area, stay upwind and use SCBA with specialist hazmat controls. Keep incompatible water/moisture tactics under incident command, use compatible dry or directed agents and watch for re-ignition.
Firefighter training notes: Training for UN 2466 should emphasize reactivity, moisture control, compatible extinguishing media, re-ignition checks, SCBA use, decontamination and runoff control. Use ERG 143, SDS and local SOP.
Regulatory context: Potassium superoxide is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Potassium superoxide should be stored dry in sealed compatible containers away from water, moisture, acids, oxidizers/reducing agents where incompatible, heat and ignition sources. Keep compatible dry media available.
UN 2466 Quick Details
Common Hazards of UN 2466
- STRONG OXIDIZER and reactive peroxide/superoxide; may explode from friction, heat or contamination.
- Reacts violently with water, producing oxygen, heat and caustic potassium hydroxide.
- Can ignite combustibles and greatly intensify fire.
- Contact with fuels, oils, organics, reducing agents or acids can cause violent reaction.
- Water, foam and CO2 can worsen the reaction or spread caustic oxidizer contamination.
- Fire may produce irritating/toxic fumes and oxygen-rich conditions.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Yellow to orange-yellow granular solid or powder. Odorless. Highly reactive oxidizer.
| Also known as | Potassium dioxidePotassium hyperoxidePotassium tetraoxideDipotassium dioxide |
| CAS Number | 12030-88-5 |
| Appearance | Yellow to orange-yellow granular solid or powder. Odorless. Highly reactive oxidizer. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Not applicable (decomposes above 560C/1040F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water, generating heat and oxygen; may ignite combustibles nearby |
Fireground Response Guidance — UN 2466
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and dry, compatible protective clothing. Protect against fire, caustic/oxidizer dust and reaction products; exclude moisture from PPE/work area.
Isolation & Evacuation
First Actions for a UN 2466 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Avoid breathing vapor, dust, gas, mist, smoke or fumes and avoid skin or eye contact.
- Keep incompatible water or moisture controls strictly under incident command because reaction or re-ignition hazards are severe.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 143, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2466 — Potassium superoxideUse 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.