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

Ammonia gas (CAS 7664-41-7): storage and disposal

Ammonia gas is held in universities as a liquefied gas in a cylinder, a very different item from the bench ammonia solution on the prep room shelf. It is flammable, toxic if inhaled and causes severe skin burns and eye damage, and it is very toxic to aquatic life. Its cylinder is a pressure container, which decides the route, and most cylinders go back to the gas supplier.

CAS number
7664-41-7
Form
Gas
Storage class
Flammable
Signal word
Danger
Usual EWC code
16 05 04*
  • Gas under pressure pictogramGas under pressure
  • Corrosive pictogramCorrosive
  • Acute toxicity pictogramAcute toxicity
  • Hazardous to the environment pictogramHazardous to the environment

This chemical is a manual enquiry

This is held as a compressed gas. Cylinders are usually returned to the supplier or handled separately, and they do not go into a laboratory pack.

Held as a compressed or liquefied gas in a pressure container.

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

Cylinders hold it as a liquid under pressure, usually in a small size kept for one research group. Stand each one upright and secured, ventilated at high level because the gas is lighter than air, and away from heat and ignition sources. Its partners matter more than the shelf. Calcium hypochlorite, sodium hypochlorite, chloramine T and sodium dichloroisocyanurate form toxic chloramine gases with it, and those are ordinary disinfectants that drift into any store. Iodine forms sensitive, violently reacting products, and mercury can form unstable compounds, so an old manometer nearby is a real concern. Copper and brass fittings suffer too, as ammonia attacks them. Acid and corrosive stock also go elsewhere. Do not puncture or vent the cylinder.

How to tell it has deteriorated

A fine white bloom on the necks of nearby hydrochloric acid bottles is often the first thing you see, because ammonia and acid vapour meet in the air and leave a solid deposit. That finding says two things: gas is escaping and acid is stored too close. Blue-green staining on brass or copper fittings is the other classic sign, and a regulator with that colour should not be trusted. The sharp smell is easy to recognise at low levels. Inside the cylinder the gas does not change with age and gives few visible signs, so rust, dents and an unreadable label are the remaining checks. Report any smell or staining straight away, and do not touch the valve.

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.

Code 16 05 04* is the entry for gases in pressure containers holding hazardous substances, and it applies to this cylinder rather than to any bottle of ammonia solution beside it. Those are separate wastes, so keep them separate in your list when clearing a store. A lab pack cannot take the cylinder, because pressure containers do not go in one. Ask the gas supplier first, as most cylinders belong to them. If no owner can be found, or the valve or regulator looks corroded, send a manual enquiry saying so. Ammonia gas is not quoted online, and a store assessment is recommended. Leave it upright, secured and in place meanwhile, and nobody should vent it.

Waste codes and transport details for Ammonia gas
EWC code, laboratory chemicals16 05 04*
Hazardous wasteYes

Gases in pressure containers are assessed by manual enquiry, usually with return to the cylinder owner.

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

  • Acetic acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Calcium hypochloriteHypochlorites and ammonia or amines form toxic chloramine gases.
  • Chloramine THypochlorites and ammonia or amines form toxic chloramine gases.
  • Hydrochloric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Hydrogen peroxideOxidisers can ignite flammable materials or make a fire far more intense.
  • IodineIodine forms sensitive or violently reacting products with ammonia and reactive metals.
  • MercuryMercury forms amalgams or unstable compounds with these materials.
  • Nitric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
Show 7 more
  • 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 dichloroisocyanurateHypochlorites and ammonia or amines form toxic chloramine gases.
  • Sodium hypochloriteHypochlorites and ammonia or amines form toxic chloramine gases.
  • Sulfuric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Thionyl chlorideA leak of corrosive stock can break down flammable containers and feed a fire.
  • Zinc chlorideA leak of corrosive stock can break down flammable containers and feed a fire.

Common quantities we collect

Usually held as: cylinder.

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

  • H221 Flammable gas.
  • H280 Contains gas under pressure; may explode if heated.
  • H314 Causes severe skin burns and eye damage.
  • H331 Toxic if inhaled.
  • H400 Very toxic to aquatic life.
  • H411 Toxic to aquatic life with long lasting effects.
Precautionary statements
  • P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P260 Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264 Wash hands and exposed skin thoroughly after handling.
  • P271 Use only outdoors or in a well-ventilated area.
  • P273 Avoid release to the environment.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
  • 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.
  • P377 Leaking gas fire: Do not extinguish, unless leak can be stopped safely.
  • P381 In case of leakage, eliminate all ignition sources.
  • P391 Collect spillage.
  • P403 Store in a well-ventilated place.
  • 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.
  • P317 Get medical help.
  • P319 Get medical help if you feel unwell.
  • P410+P403 Protect from sunlight. Store in a well-ventilated place.

Substance as classified, dilutions may differ.

Questions

Is ammonia gas in a cylinder handled the same way as our bench ammonia solution?

No. The solution is a bottled liquid chemical, whereas the cylinder holds liquefied gas under pressure and cannot go in a lab pack. List them separately in any clear out, and do not assume that a price or route for one tells you anything about the other.

Can disinfectant tablets stay in the same store as an ammonia cylinder?

No. Chlorine releasing disinfectants such as sodium dichloroisocyanurate form toxic chloramine gases with ammonia, and any leak from the cylinder could reach them. Move the disinfectant, not the cylinder, to its own space. Cleaning teams often leave these products in a store without realising what else is kept there.

The brass fitting on our regulator has turned green. Can we keep using it?

No. Ammonia attacks copper alloys, and green staining suggests the fitting has already been affected and possibly that gas has been escaping. Close nothing by force, stop using the regulator and report it. A supplier or specialist can then decide what should happen to the cylinder and its fittings.

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 H3N. EC number 231-635-3.

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