Chemical waste disposal for hospitals and healthcare

Chemical waste in a hospital is scattered. It lives in small quantities in many departments, usually managed by people for whom waste is a minor part of the job. These are the places where it most often collects:

• histopathology and cellular pathology, with formalin, xylene, alcohols and stains
• theatres and clinics, with formalin specimen pots and surplus fixative
• endoscopy, with high-level disinfectants such as peracetic acid and ortho-phthalaldehyde
• radiology and dental units still running wet film, with fixer and developer
• pharmacy, with expired stock and non-medicinal chemicals
• estates and sterile services, with cleaning chemicals, descalers and maintenance products

Some waste stays out of a routine collection. Controlled drugs, radioactive waste from nuclear medicine, compressed gas cylinders, asbestos, explosives and anything unstable, such as dried picric acid in an old laboratory store, are handled as a manual enquiry.

• the site, department and contact name for each list
• chemical name, concentration, container size and number of containers
• whether the waste is unused stock, spent working solution, or mixed
• any contamination with blood, tissue or infectious material, stated plainly
• loading bay access, security arrangements and any permit needed for a clinical area
• purchase order and cost centre details, split by department if finance needs that

Spent solutions need a little extra thought, because a working solution is no longer what the supplier's safety data sheet describes. Xylene from a tissue processor carries dissolved wax, and a used fixative may have picked up tissue residues. Say so on the list. A carrier can plan for an accurate description, and the receiving site can reject a load that turns out to be something else.

HTM 07-01 is the reference for healthcare waste in England, with the current edition published in 2023. Its colour-coding is familiar to every ward: yellow for infectious waste needing incineration, including chemically or medicinally contaminated waste, orange for infectious waste suitable for alternative treatment, purple for cytotoxic and cytostatic waste, blue for other medicines, red for anatomical waste, yellow and black for offensive waste. Amalgam has its own white container.

Chemicals do not have a colour of their own, and that is where errors creep in. HTM 07-01 is clear that waste chemicals should not be placed in clinical, offensive or municipal streams, and that this mixing is prohibited in England and Wales. Chemical waste is segregated and packaged according to transport classification and chemical compatibility, and it should normally carry 18 01 06* or 18 01 07, with photochemicals coded under 09 01. Fixer and developer also have their own containers and should not be mixed with each other or anything else.

There is a limit to this guidance. HTM 07-01 notes that its chemicals section is not intended for assessing laboratory chemicals and reagents, so hospital laboratories need to assess their stock under the technical guidance on waste. Yellow-stream waste is confined to items that are both infectious and chemically contaminated, such as some samples and diagnostic kits. A bottle of expired reagent does not qualify, however convenient the yellow bin may be.

In Scotland and Northern Ireland, HTM 07-01 notes that different colour-coding systems apply, so check your local standard before relying on the English colours.

Most hospital chemical waste is small and irregular, so a central collection only works if departments know what to do between visits. It tends to work best when a waste officer holds one list per department and asks each one to report the same things: what is waiting, how much, and in what container. Labs may need a regular visit. Theatres and outpatient clinics may only need attention a couple of times a year.

Traceability matters more as the number of departments grows. HTM 07-01 says containers should be tagged or labelled in a way that identifies the facility and the place or ward of origin. A chemical bottle with no department on it creates a question nobody can answer once it has reached the central store.

Central storage has its own requirement. HTM 07-01's guidance on storage calls for chemical waste to be kept separately by hazard, with appropriate firefighting provision, because water will not typically be used in such an area. If your compound shares a room with clinical bins, it is worth reviewing before the next audit.

Cytotoxic and cytostatic stock raises a separate concern. It is covered by HSE guidance under COSHH, and the waste needs handling as such. Our pharmaceutical waste collection page goes into how medicines streams are kept apart.

Permitted healthcare waste sites in England and Wales must obtain pre-acceptance audits from producers. HTM 07-01 sets out pre-acceptance audit frequencies: before the first batch, every 12 months for sites producing 5 tonnes or more of clinical waste a year, every 2 years for dentists, veterinary practices and research laboratories, and every 5 years for other healthcare sites producing less than 5 tonnes a year. Add these to the same calendar as your chemical collections, since new chemical streams will not appear on an audit unless someone mentions them.

Your consignment note archive is the proof of all this. In England, GOV.UK requires notes, consignee returns and related documents to be kept for three years at the premises that produced or stored the waste. If a return does not arrive, ask for it in writing, because you need it to complete your records. An NHS trust with several sites should keep each hospital's register distinct, even when one team manages them all. Consignment notes in Wales use a premises code or an exempt prefix. Those in Scotland carry a code issued by SEPA. We treat Northern Ireland collections as a manual enquiry for now.

Hospitals change quickly and their cupboards do not. A department relocates, a test moves off-site or a laboratory stops a method, and the reagents remain in a store nobody now owns. Old histology stores may hold picric acid, mercury-based fixatives and stains that are no longer in routine use. Mercury thermometers and sphygmomanometers may still lie in a cupboard long after they went out of service, and they are hazardous waste too.

Mergers, refurbishments and estate rationalisation are the usual moments when these turn up. Please do not ask a porter or a maintenance contractor to clear them. If the contents are old or uncertain, a chemical store assessment gives you a specialist's view of the stock and a list you can act on.