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

Ammonium nitrate (CAS 6484-52-2): storage and disposal

Ammonium nitrate is a white solid oxidiser kept in school, college and university stores. It is classified as able to intensify fire and as causing serious eye irritation, with a Danger signal word. It cakes on storage, and contamination with organic material or metals raises the risk, so a tub that has sat for years deserves a careful look.

CAS number
6484-52-2
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

Anything that could burn or react with it is the thing to keep away, and the list on a real shelf is long: peroxide forming ethers such as diethyl ether and dioxane, activated charcoal, aluminium powder, copper metal, and hypochlorites. Heating under confinement can cause detonation, so the cupboard should not sit beside a radiator or a heat source. Use the oxidiser space on non-combustible shelving, apart from flammable, acid, alkali and corrosive stock. Keep the lid tight, wear eye protection, and date the tub. A school prep room that stores it with fertiliser sacks should keep the two lots described separately.

How to tell it has deteriorated

Look at the condition of the container and label. A cracked tub, a crust at the neck and a faded or stained label show the seal has failed. The solid cakes on storage, so a hard lump at the base is expected on old stock, though it should be recorded. The more serious signs are contamination: dust, paper fibre or scrapings of organic material inside the tub, metal filings or a stain from nearby metal, and spilt crystals on card or wood. Do not break up a lump or scrape residue. Report it and leave the tub where it is.

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 code 16 05 06* carries an asterisk, which marks it as hazardous waste, and 16 05 07* applies where it is a discarded inorganic chemical outside a lab pack. UN 1942 is its transport number. Because contamination raises the risk, the record should note any organic dust, metal or spilt crystals around the tub, and whether it has caked. As an oxidiser it is packed apart from flammable, acid and organic stock and never beside charcoal or powdered metal. It is not put in a sink, drain, general waste bin or skip.

Waste codes and transport details for Ammonium nitrate
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

  • 1,2-DimethoxyethanePeroxide forming ethers can ignite or explode with strong oxidisers.
  • 1,4-DioxanePeroxide forming ethers can ignite or explode with strong oxidisers.
  • Activated charcoalStrong oxidisers can form mixtures with these materials that burn fiercely or explode.
  • Aluminium powderStrong oxidisers can form mixtures with these materials that burn fiercely or explode.
  • Calcium hypochloriteHypochlorites and ammonia or amines form toxic chloramine gases.
  • Chloramine THypochlorites and ammonia or amines form toxic chloramine gases.
  • Copper metalAmmonium nitrate forms mixtures with these materials that can detonate.
  • Diethyl etherPeroxide forming ethers can ignite or explode with strong oxidisers.
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  • Diisopropyl etherPeroxide forming ethers can ignite or explode with strong oxidisers.
  • GlucoseStrong oxidisers can form mixtures with these materials that burn fiercely or explode.
  • Magnesium ribbonStrong oxidisers can form mixtures with these materials that burn fiercely or explode.
  • Potassium chlorateChlorates and ammonium salts can form unstable ammonium chlorate.
  • Potassium cyanideCyanides react violently with strong oxidisers.
  • Potassium hydroxideStrong alkalis release ammonia gas from ammonium salts.
  • Red phosphorusStrong oxidisers can form mixtures with these materials that burn fiercely or explode.
  • Sodium chlorateChlorates and ammonium salts can form unstable ammonium chlorate.
  • Sodium cyanideCyanides react violently with strong oxidisers.
  • Sodium dichloroisocyanurateHypochlorites and ammonia or amines form toxic chloramine gases.
  • Sodium hydroxideStrong alkalis release ammonia gas from ammonium salts.
  • Sodium hypochloriteHypochlorites and ammonia or amines form toxic chloramine gases.
  • Sodium nitriteNitrites and ammonium salts can react violently on heating.
  • SucroseStrong oxidisers can form mixtures with these materials that burn fiercely or explode.

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.
  • H319 Causes serious eye 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+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
  • P271 Use only outdoors or in a well-ventilated area.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • 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.
  • P337+P317 If eye irritation persists: Get medical help.
  • 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 has our ammonium nitrate set solid?

It cakes on storage. Do not break the lump up. Record the tub as caked, check that the lid is tight and make sure it is away from heat, then list it for collection.

What counts as contamination?

Organic material or metals in or around the stock, such as paper fibre, dust, scrapings or metal filings. Contamination raises the risk, so report it, leave the tub where it is and describe what you can see.

Why is heat a problem?

Heating under confinement can cause detonation. Keep the tub away from radiators, hot pipes and ovens, with the lid on and the stock in the oxidiser space on non-combustible shelving.

Can it be stored with other ammonium salts?

Keep it with oxidisers, not in a general run of salts. Ammonium chloride, carbonate and acetate sit apart from chlorates, and the nitrate has its own oxidiser space, away from charcoal and metals.

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 H4N2O3. EC number 229-347-8.

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