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

Manganese metal (CAS 7439-96-5): storage and disposal

Manganese is held as brittle flakes in school, college and university stores, and the jar is often one of the older ones on the metals shelf. It is not classified as hazardous on the sources we checked, but it remains a chemical waste that needs an accurate description. Air and moisture dull the flakes, which makes the age of the jar the main question.

CAS number
7439-96-5
Form
Solid
Storage class
General
Usual EWC code
16 05 09

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 general 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

Inspect the jar from outside without opening or tipping it. Bright, silvery flakes may show limited surface oxidation, while dull brown or black surfaces can indicate exposure to air and moisture. Manganese does best in a dry, labelled, well organised general store, dated on arrival, with the lid screwed tight and a dry shelf beneath. Keep it away from leaking bottles and wet stock, because damp is what dulls it. Separate it from food grade supplies. It can share the metals shelf with other unclassified metals, but each jar needs its own label so that flakes of different metals are never confused.

How to tell it has deteriorated

Manganese tarnishes. The silvery grey surface darkens to a dull brown or black film in air, and flakes kept in a damp store go dull faster and may sit in a layer of fine dark dust at the bottom of the jar. Light darkening is normal on old stock and does not change how the jar is handled. Look at the container for a faded label, a corroded metal lid, a cracked jar and a lost date of receipt. Flakes that have stuck together in a damp lump, or sit with an unknown residue, should be recorded as contaminated rather than as clean manganese.

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 non-regulated or low hazard laboratory pack with compatible chemicals.

Write down the form, the amount left, the colour of the flakes and the state of the label. Manganese is not classified as hazardous on the sources we checked, so it takes the code 16 05 09 with a waste transfer note, but it stays a chemical waste and is described as one. Specialist collection is the only route, and it must not go into the sink, the drain, the general bin or the skip, and nobody should try to clean or process the flakes first. Damp lumps and unlabelled jars are described honestly so the collector can pack them correctly.

Waste codes and transport details for Manganese metal
EWC code, laboratory chemicals16 05 09
Hazardous wasteNo

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

Common quantities we collect

Usually held as: flakes.

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

Questions

Does manganese flake go off with age?

It darkens rather than going off. Flakes dull to brown or black in air and damp, which is normal on old stock. No fixed life is set for it, so judge by the label, the lid and whether the contents have turned into a damp lump.

Is manganese metal classed as hazardous waste?

It is not classified as hazardous on the sources we checked, so it takes the code without an asterisk. It is still a chemical waste and needs an accurate description, so it must not go in the general bin or down a drain.

Can manganese flakes go on the same shelf as other metals?

Yes, provided each jar has its own legible label and the shelf is dry. Flakes of different metals look alike once tarnished, so labels matter more than position. Keep them away from damp and from leaking bottles.

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 Mn. EC number 231-105-1.

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