Potassium Permanganate: Uses, Oxidiser Hazards and SDS Notes

Potassium permanganate (KMnO4, CAS 7722-64-7) forms dark purple to almost black crystals that dissolve in water to give an intensely violet solution. It is a strong oxidiser, which is the root of both its usefulness and its hazards. It has been used for well over a century as a disinfectant, an oxidant in industry and a titration reagent in laboratories.

Common uses

• Drinking-water and wastewater treatment, to oxidise iron, manganese and hydrogen sulphide and to control taste and odour.
• Aquaculture and fish-pond treatment against parasites and fungi, where dosing must be controlled.
• Industrial processes: chemical synthesis, bleaching, and cleaning of gas streams.
• Laboratory titrations (permanganometry) and organic oxidations.
• Metal finishing, for surface treatments and the cleaning of printed circuit boards.
• Veterinary and some regulated medicinal uses, as dilute solutions, where national pharmaceutical rules apply.

Why classification is serious

Potassium permanganate is classified as an oxidising solid (category 2, H272: may intensify fire), harmful if swallowed (H302), causing severe skin burns and eye damage (H314), and very toxic to aquatic life with long lasting effects (H400 and H410). The signal word is Danger and the pictograms are flame over circle (GHS03), corrosion (GHS05), exclamation mark (GHS07) and environment (GHS09). Confirm the entry that currently applies to your grade, since concentration thresholds for mixtures vary.

Oxidising solids do not burn themselves, but they feed fire and can ignite combustible material on contact. Permanganate in contact with glycerol, glycols, alcohols, sulfuric acid, powdered metals or other organic and reducing materials can react violently or ignite, in some cases within seconds. This is a well-known cause of laboratory and demonstration accidents.

Handling

Wear goggles, gloves and protective clothing, avoid creating dust, and never mix with reducing agents or flammable materials. The dust stains skin and surfaces brown, which is harmless in itself but a visible sign of exposure. Handle with clean, dry tools, and do not return spilled material to the original container, because contamination can start a reaction.

Storage and compatibility

Store in cool, dry, tightly closed containers, in an area free from combustible and organic materials, acids, reducing agents, peroxides, hydrogen peroxide and flammable liquids. Use a dedicated oxidiser section in the warehouse with no wooden pallets or paper packaging nearby if practical. Our storage compatibility guide explains how to segregate oxidisers. Section 7 of the SDS should say this clearly.

Spills, fire and disposal

Clean up spills with inert, non-combustible materials and place them in labelled containers, and never use sawdust, paper or cloth. For fires, flooding with plenty of water is usually recommended for oxidisers, since there is no point trying to smother them, but follow your SDS and the fire service. Do not allow permanganate to reach drains or surface water, because of its aquatic toxicity. Waste is typically treated by reduction to manganese dioxide before disposal under local regulations.

Transport and documents

It is a Class 5.1 oxidising substance for transport. Check the current UN number and packing group. Note that in some jurisdictions potassium permanganate is a monitored or controlled chemical because it can be used illicitly, so you may need to keep sales records or apply for a licence. Confirm the rules in your country and your customer's. The data we hold is on the potassium permanganate page. Compare it with another oxidising compound in our silver nitrate guide.