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

Chlorhexidine digluconate (CAS 18472-51-0): storage and disposal

Dental surgeries, veterinary practices, pharmacies and school and college labs hold chlorhexidine digluconate in very different strengths, from a dilute rinse to a concentrate. Classification as causing serious eye damage and as very toxic to aquatic life with long lasting effects applies to the substance, and a weaker solution may be less hazardous, though it still has to be treated as chemical waste.

CAS number
18472-51-0
Form
Solution
Storage class
General
Signal word
Danger
Usual EWC code
16 05 06*
  • Corrosive pictogramCorrosive
  • Hazardous to the environment pictogramHazardous to the environment

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

In a dental surgery or clinic the bottle on the shelf is likely to be a weak rinse or antiseptic, and in a university store it may be a concentrate. They should not share a shelf unlabelled, because the strength on the label decides how the container is described later. Keep the bottles upright on a tray at a sensible height, since the eye damage classification makes a splash from a high shelf a real concern. Chlorhexidine is a poor mix with bleach-type cleaning products, which can leave brown staining and residues, so a cleaning cupboard is the wrong neighbour. Date each bottle when received and keep decanted stock clearly labelled.

How to tell it has deteriorated

A clear, colourless to pale liquid is normal. Look for cloudiness, a deposit on the bottom, a changed colour, or a crust of dried residue at the neck of a rinse bottle in a surgery. Brown marks on a shelf, a worktop or a bottle label may point to contact with bleach-type products. Whether a deposit is harmful is not something a holder needs to work out. It is a sign the bottle is not in good condition. Other checks are leaking pumps, perished seals, a faded strength on the label and a bottle with no date.

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.

How it is grouped and packed starts with the strength. A 20% concentrate, a 4% scrub and a 0.2% rinse are listed as separate items with their volumes, and a collection normally packs liquids of this kind together in compatible groups in sealed UN approved packaging. The very toxic to aquatic life classification is the main reason the answer is never a drain, and it is the reason dilute rinse should be gathered rather than washed away at the end of a clinic day. A veterinary practice often uses 18 02 05*, a human healthcare setting 18 01 06*, and a school or college 16 05 06*.

Waste codes and transport details for Chlorhexidine digluconate
EWC code, laboratory chemicals16 05 06*
Discarded organic chemical, not a laboratory pack16 05 08*
Human healthcare setting18 01 06*
Veterinary setting18 02 05*
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.

Common quantities we collect

Usually held as: 0.2%, 2%, 4%, 20% concentrate.

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

  • H318 Causes serious eye damage.
  • H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
  • P264 Wash hands and exposed skin thoroughly after handling.
  • P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
  • P270 Do not eat, drink or smoke when using this product.
  • P273 Avoid release to the environment.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P301+P317 IF SWALLOWED: Get medical help.
  • P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P317 Get medical help.
  • P330 Rinse mouth.
  • P391 Collect spillage.
  • P501 Dispose of contents and container in accordance with local, regional, national and international regulations.

Substance as classified, dilutions may differ.

Questions

What should we do with small amounts of leftover chlorhexidine rinse?

Leftover rinse is never put into a drain. The substance is classified as very toxic to aquatic life with long lasting effects. Gather leftover rinse and unwanted bottles in labelled containers and arrange specialist collection, including weak solutions.

Do different strengths need separate entries?

Yes. List each strength, such as the 0.2% rinse, the 2% or 4% solution and any 20% concentrate, with its volume. A dilute solution may be less hazardous than the concentrate, but it is still listed accurately.

Why has our chlorhexidine bottle gone cloudy?

Cloudiness or a deposit means the bottle is not in good condition, and contact with other products may be involved. Do not try to clear it or use it. Label it and list it for collection.

Is it safe to keep chlorhexidine next to cleaning products?

Not with bleach-type products, which can stain and leave residues. Keep antiseptic stock in the clinical or chemical store, upright and labelled, and keep it below eye height because of the serious eye damage classification.

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 C34H54Cl2N10O14. EC number 242-354-0.

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