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

Lithium metal (CAS 7439-93-2): storage and disposal

Lithium metal reaches schools, colleges and universities as lumps or ribbon, held under oil or inert gas. It reacts with water and releases flammable hydrogen, more gently than sodium does, and it causes severe skin burns and eye damage. Because it reacts with air as well, the condition of old stock decides how it is handled, and that cannot be judged from a web form. Each holding therefore goes through a manual enquiry.

CAS number
7439-93-2
Form
Solid
Storage class
Flammable
Signal word
Danger
Usual EWC code
16 05 06*
  • Flammable pictogramFlammable
  • Corrosive pictogramCorrosive

This chemical is a manual enquiry

This can become unstable or explosive, especially if it is old or has dried out. Nobody should move it until someone competent has looked at it, so we start with a conversation and usually a store assessment.

Reacts with water and air, and condition of old stock cannot be judged from a web form.

It cannot be priced through a form. Please do not open or move it. Call us or send an enquiry and we will talk through the safe next step, which is often a store assessment.

What to do this week

  1. Leave it where it is. If it looks old, crystalline or damaged, do not open or move it and keep people away from the shelf.
  2. Write down the label wording, the rough age and where it is stored, from a safe distance.
  3. Send us those details, and a photo if you can take one without touching it.

Safe storage in a school or lab

In a school prep room lithium usually shares a dry, fire-resistant cabinet with the other alkali metals. Being the least dense metal, it is lighter than its oil, so pieces tend to float, and the top face can sit at the oil line even in a full jar. Holders often take that for a fault, or are tempted to open the jar and press the pieces down, which should not be done. Ammonia solution, formalin and hydrochloric acid need to be well away, as it reacts with anything water based. Chloroform, dichloromethane and carbon tetrachloride can react explosively with alkali metals, so a shared solvent shelf is a poor home. University stock sealed under inert gas should stay sealed until someone competent has seen it.

How to tell it has deteriorated

Expect a dull grey surface, as lithium tarnishes in air, and a floating piece with a darker top face is common. Trouble looks different: a dark nitride or oxide coating across the whole piece, and no longer confined to where it breaks the oil. Lithium is unusual among the alkali metals in reacting with nitrogen as well as oxygen, which is why exposed metal can turn so dark. A low oil level and a damaged container are warning signs in their own right. Beyond that it gives few visual signs, and what lies under a coating cannot be seen from outside. If you find any of these, do not open or move the jar, and do not cut a piece to look inside. Keep the area dry and ask for specialist advice.

How it must be disposed of

This does not go through our standard collection route. It is arranged by manual enquiry, and never goes down the drain or into general waste.

It leaves only after a manual enquiry, since this site does not quote for it online and the online quote path does not accept it. Condition is the reason: a coating seen through glass says little, and how far old stock has reacted cannot be judged from a web form. A store assessment is recommended, with a competent chemist seeing it in person, and a warning sign may bring in an explosives or emergency specialist. For the enquiry, give the number of jars, whether the metal is under oil or inert gas, how far any coating has spread and how much oil remains. Do not open it, move it or try to make it safe in the meantime, and keep it out of any sink, drain, bin or skip.

Waste codes and transport details for Lithium metal
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

  • OxidiserOxidisers can ignite flammable materials or make a fire far more intense.
  • AcidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • CorrosiveA leak of corrosive stock can break down flammable containers and feed a fire.

Named chemicals to keep apart

  • 1,1,1-TrichloroethaneAlkali metals can react explosively with chlorinated solvents.
  • 1,2-DichloroethaneAlkali metals can react explosively with chlorinated solvents.
  • Acetic acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Ammonia solutionReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Calcium hypochloriteOxidisers can ignite flammable materials or make a fire far more intense.
  • Carbon tetrachlorideAlkali metals can react explosively with chlorinated solvents.
  • ChloroformAlkali metals can react explosively with chlorinated solvents.
  • DichloromethaneAlkali metals can react explosively with chlorinated solvents.
Show 13 more
  • FormalinReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Hydrochloric acidReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Hydrogen peroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Nitric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Potassium nitrateOxidisers can ignite flammable materials or make a fire far more intense.
  • Potassium permanganateOxidisers can ignite flammable materials or make a fire far more intense.
  • Sodium hydroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Sodium hypochloriteReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
  • Sulfuric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • TetrachloroethyleneAlkali metals can react explosively with chlorinated solvents.
  • Thionyl chlorideA leak of corrosive stock can break down flammable containers and feed a fire.
  • TrichloroethyleneAlkali metals can react explosively with chlorinated solvents.
  • Zinc chlorideA leak of corrosive stock can break down flammable containers and feed a fire.

Common quantities we collect

Usually held as: lumps under oil.

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

  • H260 In contact with water releases flammable gases which may ignite spontaneously.
  • H314 Causes severe skin burns and eye damage.
Precautionary statements
  • P223 Do not allow contact with water.
  • P231+P232 Handle and store contents under inert gas. Protect from moisture.
  • P260 Do not breathe dust, fume, gas, mist, vapours or spray.
  • P264 Wash hands and exposed skin thoroughly after handling.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
  • P302+P335+P334 IF ON SKIN: Brush off loose particles from skin. Immerse in cool water or wrap in wet bandages.
  • P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
  • P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
  • P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P316 Get emergency medical help immediately.
  • P321 Specific treatment (see supplemental first aid instruction on this label).
  • P363 Wash contaminated clothing before reuse.
  • P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
  • P402+P404 Store in a dry place. Store in a closed container.
  • 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 the lithium floating in our jar? Is something wrong?

Floating is normal, because lithium is less dense than the oil. It does not mean the jar has failed. Do look at how much oil remains, because a low level is a warning sign. Pressing the pieces down or adding oil would mean opening the jar, which should not be done.

Lithium reacts more gently than sodium. Does that make it a routine item?

It does not. The reaction with water is gentler, but it still releases flammable hydrogen, and the metal causes severe skin burns. Old stock also has to be seen before anyone can say what state it is in, so it goes through the same manual enquiry.

The whole piece has turned black. What has happened to it?

A dark coating across the whole piece is nitride or oxide, formed where air has reached the metal over time. It points to lost protection, usually a low oil level or a failed seal. Leave the jar where it is and describe the colour and oil level in your enquiry.

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 Li. EC number 231-102-5.

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