UN 1491 — Potassium peroxide
Placard: Oxidizer. ERG Guide 144. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1491 is Potassium peroxide, a water-reactive Class 5 oxidizer assigned to ERG Guide 144. It can release heat and oxygen on contact with water and may form corrosive alkaline solution.
Hazard overview: UN 1491 presents oxidizer, water-reactive peroxide and corrosive runoff hazards. Direct water contact may release heat and oxygen, while fuels, organics or contamination can intensify fire or decomposition.
Response guidance: For a UN 1491 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 144. 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 1491 should emphasize oxidizer behavior, water-reactive peroxide hazards, oxygen release, corrosive alkaline runoff, contamination control and compatible extinguishing decisions. Use ERG 144, SDS and local SOP.
Regulatory context: Potassium peroxide 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: Potassium peroxide should be stored dry in compatible oxidizer storage away from water where incompatible, fuels, organics, reducing agents, acids, heat and contamination. Keep containers closed, clearly labeled and separated from combustible packaging or spilled residues.
UN 1491 Quick Details
Common Hazards of UN 1491
- STRONG OXIDIZER and WATER-REACTIVE; contact with water can release heat and oxygen and form corrosive alkaline solution.
- May ignite combustibles such as wood, paper, oil, clothing, packaging or contaminated absorbents.
- May react violently with water, acids, fuels, organic materials, reducing agents or contamination.
- Containers may rupture or explode when heated.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may spread oxidizing and corrosive contamination.
- Flammable or toxic gases may accumulate in confined containers or poorly ventilated areas.
Chemical Identity & Physical Properties
Yellow to orange-yellow granular solid or powder. Odorless. Hygroscopic and highly reactive oxidizer.
| Also known as | Potassium dioxideDipotassium peroxidePotassium superoxide (historical)Peroxide of potassium |
| CAS Number | 17014-71-0 |
| Appearance | Yellow to orange-yellow granular solid or powder. Odorless. Hygroscopic and highly reactive oxidizer. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Decomposes at approximately 490C (914F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water, releasing oxygen and heat, forming corrosive potassium hydroxide solution |
Fireground Response Guidance — UN 1491
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, dust, decomposition, corrosive mist or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS because water contact can form corrosive alkaline solution.
Isolation & Evacuation
First Actions for a UN 1491 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 144, shipping papers, SDS and local SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1491 — Potassium peroxideUse 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.