UN 2466 — Potassium superoxide
Placard: Oxidizer. ERG Guide 143. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2466 At a Glance
UN 2466 (Potassium superoxide) is listed as DOT Class 5 Oxidizer and is assigned to ERG Guide 143. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
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.