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

Ethanol: safe storage and disposal

Ethanol (CAS 64-17-5) is held by nearly every kind of laboratory we serve. It comes as absolute alcohol, as graded solutions in a histology line and as industrial methylated spirits in many a school cupboard. Its GHS signal word is Danger. The hazard statements are H225 Highly flammable liquid and vapour and H319 Causes serious eye irritation.

People tend to underestimate ethanol because it is familiar. A clear alcohol flame can be hard to see in a bright room, and vapour from a spirit burner or an open bottle ignites easily. Treat it with the same respect as any other flammable solvent.

CAS number
64-17-5
Form
Liquid
Storage class
Flammable
Signal word
Danger
Usual EWC code
16 05 06*
  • Flammable pictogramFlammable
  • 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 flammable 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 of ethanol in a school or lab

Store bulk ethanol in a fire-resisting cabinet with other flammables, in its original closed container. Keep the open quantity small. Your DSEAR assessment should say how much may be out during a lesson or a shift. Do not keep it in a domestic fridge, as the internal light and thermostat can ignite vapour.

Plan for security as well. Pure alcohol is attractive to some people for reasons that have nothing to do with science, so a locked store and an accurate stock count both matter. Label every decant. A bottle of clear liquid with no label is the origin of many unknowns on a later disposal list.

How to tell ethanol has deteriorated

Ethanol itself is stable. It does not form dangerous peroxides under normal storage, and a sealed bottle will usually remain sound for many years.

What changes is its purity and its container. It absorbs water from the air, which matters for absolute grades and for histology, where dehydration depends on the alcohol's strength. A dropped level in an unopened bottle suggests a failed seal. Cloudiness, colour or a separate layer points to contamination, possibly from reuse or from being used in a process. Plastic squeeze bottles can age and crack.

Treat a contaminated bottle as a mixture of uncertain contents. Do not reuse it, and do not try to clean it up.

How ethanol must be disposed of

Ethanol goes by specialist collection, whether clean or used. It does not go down the sink.

SettingUsual List of Wastes codeHazardous
Laboratory chemical, including school and university16 05 06*Yes
Discarded organic chemical, not in a laboratory pack16 05 08*Yes
Human healthcare setting18 01 06*Yes
Veterinary setting18 02 05*Yes

The solvents entry 20 01 13* belongs to municipal collections and is not the normal code for a laboratory collection. For transport, ethanol is UN 1170, packing group II. Alcohols that are not otherwise specified, which can include denatured products, are UN 1987.

Used processing alcohol needs a proper description. The consignment note guidance asks for the chemical components of the waste, and the short code alone will not do. "Used ethanol from tissue processing, may contain xylene and tissue residue" is useful to a receiving site. "Alcohol" is not.

Labs with a steady volume often move to scheduled solvent waste collection, so containers do not build up beyond what the cabinet and the assessment allow.

Waste codes and transport details for Ethanol
EWC code, laboratory chemicals16 05 06*
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 ethanol with

  • Nitric acid reacts violently with organic solvents. Waste bottles can burst this way, so never add it to an alcohol waste bottle.
  • Silver nitrate can form explosive silver compounds with ethanol. School and histology stains make this pairing a live one.
  • Potassium permanganate can ignite or explode with ethanol.
  • Hydrogen peroxide in concentrated form can form unstable organic peroxides.
  • Sodium hypochlorite and other chlorine-releasing disinfectants react, releasing heat and chlorinated products.
  • Bromine, chromium trioxide, perchloric acid and osmium tetroxide should all be kept well away.

Keep it separate from oxidisers, corrosives and acids as storage classes.

  • 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.
  • BromineBromine reacts violently with ammonia, reactive metals and many solvents.
  • Calcium hypochloriteHypochlorites react with these solvents, releasing heat and chlorinated products.
  • Chloramine THypochlorites react with these solvents, releasing heat and chlorinated products.
  • Chromium trioxideChromium trioxide can ignite organic liquids on contact.
  • Hydrochloric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Hydrogen peroxideConcentrated peroxide with these liquids can form unstable organic peroxides.
  • Nitric acidNitric acid reacts violently with organic solvents and can ignite them or build pressure in waste bottles.
Show 10 more
  • Osmium tetroxideOsmium tetroxide is a strong oxidiser that reacts with these materials and can release toxic gas.
  • Perchloric acidPerchloric acid forms explosive mixtures with organic material.
  • Potassium nitrateOxidisers can ignite flammable materials or make a fire far more intense.
  • Potassium permanganatePermanganate can ignite or explode with these materials.
  • Silver nitrateSilver nitrate can form explosive silver compounds with these materials.
  • Sodium dichloroisocyanurateHypochlorites react with these solvents, releasing heat and chlorinated products.
  • Sodium hypochloriteHypochlorites react with these solvents, releasing heat and chlorinated products.
  • 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 of ethanol collected

Schools usually have a few bottles of IMS and small amounts of absolute ethanol. Histology lines can produce regular containers of used graded alcohol. Research groups may hold Winchesters and used wash solvent. Part-used bottles tend to be the bulk of what is collected, along with older stock that has lost its label.

Usually held as: absolute, 96%, 70%.

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.

Ethanol in different sectors

Schools and colleges. IMS and spirit burner fuel are the common forms. Check whether burners have been left filled during a stock check, and record what you find.

Pathology and histology. Graded alcohols are central to tissue processing and staining. Waste chemicals must stay out of clinical and offensive streams, and the healthcare guidance gives 18 01 06* for hazardous chemicals.

Pharmacy and clinics. Bulk bottles you are discarding count as chemical waste. Medicines containing alcohol have separate codes, so check how the product is classified before listing it.

Dental and veterinary practices. Small volumes are the norm. The veterinary code differs from the human healthcare one.

Hazard data from PubChem GHS classification, retrieved 31 October 2026. Guidance only. Check your own risk assessment and your supplier's safety data sheet.

Hazard statements

  • H225 Highly flammable liquid and vapour.
  • H319 Causes serious eye irritation.
Precautionary statements
  • P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P233 Keep container tightly closed.
  • P240 Ground and bond container and receiving equipment.
  • P241 Use explosion-proof electrical, ventilating and lighting equipment.
  • P242 Use non-sparking tools.
  • P243 Take action to prevent static discharges.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
  • P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
  • P403+P235 Store in a well-ventilated place. Keep cool.
  • P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
  • P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
  • P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P337+P317 If eye irritation persists: Get medical help.

Substance as classified, dilutions may differ.

Questions

Our 70% ethanol is already diluted, so is it treated differently from absolute?

No. Even at 70% it is a highly flammable liquid and vapour. A dilute solution may be less hazardous than the pure liquid, but that does not make it safe to pour away. It goes by specialist collection.

How should used histology alcohols be described?

By what they now contain. Graded alcohols that have carried fixative, clearing agent or tissue debris are no longer plain ethanol, so list the contaminants at booking and keep them apart from clean stock.

Does absolute ethanol go off once opened?

It does not spoil, but it takes up water from the air and stops being absolute. The bottle looks the same, so date it on opening and move older bottles to general solvent use or collection.

Does duty free status change how we dispose of it?

Not the route, which is still specialist collection. It affects your own stock records in some institutions, so check what your finance or compliance office needs before the bottle leaves the site.

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 C2H6O. EC number 200-578-6.

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