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Chemical collection and stock control for UK schools, universities and hospitals

Potassium iodate (CAS 7758-05-6): storage and disposal

Potassium iodate is a white crystalline oxidiser kept in school, college and university stores, mostly for titration work. It is classified as an oxidiser that may intensify fire, harmful if swallowed, and irritating to skin, eyes and the respiratory tract. Where the tub sits and what has spilt around it matter more than any change in the salt.

CAS number
7758-05-6
Form
Solid
Storage class
Oxidiser
Signal word
Danger
Usual EWC code
16 05 06*
  • Oxidising pictogramOxidising
  • Harmful or irritant pictogramHarmful or irritant

What to do this week

  1. Check the label is readable and write down the opened date if it is not already there.
  2. Check it is stored as oxidiser stock and apart from the items listed under "Do not store with".
  3. If you no longer need it, add it to your disposal list so it goes on the next collection.

Safe storage in a school or lab

One check at the shelf tells most of the story: is the tub standing in the oxidiser space, or sharing a rack with the organic reagents it was bought alongside for titration work? Move it to non-combustible shelving, apart from flammable, acid, alkali and corrosive stock and from toxic stock. Paper labels, cardboard boxes and wooden shelf liners are fuel, so a metal or plastic tray is better than bare wood. Wear eye protection and gloves when scooping, because it irritates skin and eyes, and close the lid straight away so that dust does not hang in the air in a small prep room.

How to tell it has deteriorated

A good tub holds loose, dry, white crystals or powder. This salt gives few distinctive signs of its own, so the evidence is in the container. Caking or a damp appearance means air has got in, and a crust around the neck means the lid has not been closing. Look for corroded caps, rust spots on the shelf below, stained or lifting labels and contamination with paper or organic dust. Dust and paper inside the container are the more worrying finds, as an oxidiser in contact with organic material makes a fire much worse. A tub with no date of receipt is recorded as old stock.

How it must be disposed of

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a oxidising laboratory pack with compatible chemicals.

The asterisk on 16 05 06* marks this as hazardous waste, and that is the usual code. Where it is a discarded inorganic chemical and not part of a laboratory pack, 16 05 07* applies instead. A precise description matters: container size, amount left, condition of the lid and what shares the shelf. It is packed with oxidisers only, away from flammable, acid and organic stock. A sink, drain, general waste bin or skip is never the route, and staff should not try to treat it first.

Waste codes and transport details for Potassium iodate
EWC code, laboratory chemicals16 05 06*
Discarded inorganic chemical, not a laboratory pack16 05 07*
Hazardous wasteYes

The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.

Do not store with

  • FlammableOxidisers can ignite flammable materials or make a fire far more intense.
  • AcidMany oxidisers release toxic gas or become unstable in contact with acid.
  • AlkaliSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
  • ToxicToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
  • CorrosiveCorrosive stock can react with oxidisers, releasing heat or fumes.

Named chemicals to keep apart

  • Acetic acidMany oxidisers release toxic gas or become unstable in contact with acid.
  • AcetoneOxidisers can ignite flammable materials or make a fire far more intense.
  • Ammonia solutionSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
  • EthanolOxidisers can ignite flammable materials or make a fire far more intense.
  • FormalinToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
  • HexaneOxidisers can ignite flammable materials or make a fire far more intense.
  • Hydrochloric acidMany oxidisers release toxic gas or become unstable in contact with acid.
  • Mercury(II) chlorideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
Show 9 more
  • MethanolOxidisers can ignite flammable materials or make a fire far more intense.
  • Nitric acidMany oxidisers release toxic gas or become unstable in contact with acid.
  • Potassium hydroxideSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
  • Sodium cyanideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
  • Sodium hydroxideSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
  • Sulfuric acidMany oxidisers release toxic gas or become unstable in contact with acid.
  • Thionyl chlorideCorrosive stock can react with oxidisers, releasing heat or fumes.
  • TolueneOxidisers can ignite flammable materials or make a fire far more intense.
  • Zinc chlorideCorrosive stock can react with oxidisers, releasing heat or fumes.

Common quantities we collect

Usually held as: solid.

Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.

Where it is commonly held

Hazard statements

  • H272 May intensify fire; oxidiser.
  • H302 Harmful if swallowed.
  • H315 Causes skin irritation.
  • H319 Causes serious eye irritation.
  • H335 May cause respiratory irritation.
Precautionary statements
  • P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P220 Keep away from clothing and other combustible materials.
  • P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264 Wash hands and exposed skin thoroughly after handling.
  • P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
  • P270 Do not eat, drink or smoke when using this product.
  • P271 Use only outdoors or in a well-ventilated area.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P301+P317 IF SWALLOWED: Get medical help.
  • P302+P352 IF ON SKIN: Wash with plenty of water.
  • P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
  • P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P319 Get medical help if you feel unwell.
  • P321 Specific treatment (see supplemental first aid instruction on this label).
  • P330 Rinse mouth.
  • P332+P317 If skin irritation occurs: Get medical help.
  • P337+P317 If eye irritation persists: Get medical help.
  • P362+P364 Take off contaminated clothing. And wash it before reuse.
  • P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
  • P403+P233 Store in a well-ventilated place. Keep container tightly closed.
  • P405 Store locked up.
  • P501 Dispose of contents and container in accordance with local, regional, national and international regulations.

Substance as classified, dilutions may differ.

Questions

Why is potassium iodate an oxidiser concern in a school store?

It may intensify fire, so it must not sit beside flammable or organic stock. Keep it in the oxidiser space on non-combustible shelving, and keep paper, wood and cardboard away from the tub.

How do I tell whether an old tub has gone off?

It gives few distinctive signs, so check the container: caking, damp, crust at the neck, stains on the shelf and paper dust inside. Record any undated tub as old stock and report anything contaminated.

What protective equipment is sensible?

Eye protection and gloves, since it irritates skin and eyes and may irritate the respiratory tract. Avoid raising dust, and close the lid after each use. Keep the tub away from anything organic.

Can leftover crystals go in the chemical bin?

No. It is an oxidiser and hazardous waste, so it goes by specialist collection, not into a general chemical bin, a sink or a drain. Keep it labelled in the oxidiser space until it is collected.

Guidance only. Check your own risk assessment and your supplier's safety data sheet.

Hazard data source: PubChem GHS Classification, retrieved 31 Oct 2026. Formula IKO3. EC number 231-831-9.

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