UN 2033 — Potassium monoxide
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2033 is Potassium monoxide, a corrosive water-reactive alkali metal oxide assigned to ERG Guide 154. Moisture can form hot caustic potassium hydroxide.
Hazard overview: CORROSIVE water-reactive alkali metal oxide; dust or contact may cause severe skin, eye and respiratory injury. Reacts violently with water or moist air, generating heat and corrosive potassium hydroxide solution. Reaction may cause spattering, steam and corrosive mist.
Response guidance: For a UN 2033 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 or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2033 should emphasize pressure/fire hazards, exposure routes, air monitoring, PPE selection, evacuation, decontamination and ERG/SDS verification. Use ERG 154, SDS and local SOP.
Regulatory context: Potassium monoxide 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: Potassium monoxide should be stored dry in compatible sealed containers away from water, moisture, acids, oxidizers where incompatible, heat and unauthorized access. Prevent dust generation and moisture contamination.
UN 2033 Quick Details
Common Hazards of UN 2033
- CORROSIVE water-reactive alkali metal oxide; dust or contact may cause severe skin, eye and respiratory injury.
- Reacts violently with water or moist air, generating heat and corrosive potassium hydroxide solution.
- Reaction may cause spattering, steam and corrosive mist.
- Non-combustible, but heat and caustic reaction products can worsen surrounding incidents.
- Runoff may become strongly alkaline and corrosive.
- Containers may rupture or fail when heated or contaminated with water.
- Avoid dust generation and moisture contact.
Chemical Identity & Physical Properties
Gray to white crystalline solid or powder. Odorless. Hygroscopic and reacts vigorously with moisture.
| Also known as | Potassium oxideDipotassium oxideKaliumoxidPotassium oxide (K2O) |
| CAS Number | 12136-45-7 |
| Appearance | Gray to white crystalline solid or powder. Odorless. Hygroscopic and reacts vigorously with moisture. |
| Flash Point | Not applicable (inorganic oxide) |
| Boiling Point | Decomposes before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water, generating heat and forming corrosive potassium hydroxide solution |
Fireground Response Guidance — UN 2033
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected for caustic alkali exposure.
Isolation & Evacuation
First Actions for a UN 2033 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, gas, dust, mist, smoke or fumes and avoid skin or eye contact.
- Keep water and moisture away from released solid unless incident command confirms a compatible control use.
- Do not touch damaged containers or spilled/released 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 spread, cylinder heating or unknown product identity.
- Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2033 — Potassium monoxideUse 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.