Clinical and laboratory waste collection

Our focus is the laboratory end of healthcare and research, where chemicals and clinical material meet. That typically covers:

• diagnostic kits and analyser waste, where they contain chemical preservatives or reagents
• samples and consumables that are both infectious and chemically contaminated
• chemically preserved anatomical specimens
• chemical waste from clinical laboratories, kept out of the clinical stream
• animal healthcare equivalents from veterinary and research laboratories
• part-used disinfectants and other chemicals used in clinical areas

Radioactive waste is a manual enquiry, as are controlled drugs, compressed gas cylinders, asbestos and any chemical that may be unstable. Routine ward bags and sharps bins are usually collected on a clinical waste round, and we can look at how they sit alongside your laboratory waste when reviewing your arrangements.

• a list of streams by department, with typical volumes
• for each kit or analyser waste, the product name and safety data sheet
• whether items are known to be infectious, and the hazard group if relevant
• any chemical treatment or autoclave step already applied, and its validation status
• current containers, and who collects each existing stream
• last pre-acceptance audit date and any changes since
• site contact, loading access and the person who will sign

A chart showing each waste stream, its container and its collector is a simple document, and it is often the first thing we would ask to see. If you do not have one, a walk around the lab with a notepad is usually enough to create it.

HTM 07-01 sets out the colours that most healthcare staff know. The important ones for laboratories are these. Yellow is for infectious waste requiring incineration, including chemically contaminated lab waste. Orange is for known infectious waste suitable for alternative treatment. Purple is for cytotoxic and cytostatic waste. Blue is for other medicines, and yellow and black is for offensive waste.

Colour on its own is not enough, because the choice between orange and yellow turns on chemistry. GOV.UK is firm on the point: you must only put items that are both infectious and chemically contaminated in the yellow bag stream, for example some samples and diagnostic kits. That stream is coded 18 01 03* and 18 01 06*. Infectious waste with no chemicals or pharmaceuticals is orange, under 18 01 03* alone. Treating every lab item as yellow may feel cautious, but it sends waste to a route it does not need, and it hides what is actually there.

A clean reagent bottle that has never met a patient sample is not clinical waste, whatever department it comes from. It is chemical waste and it should be classified as such. HTM 07-01 says that waste chemicals should not go in clinical, offensive or municipal streams, and also notes that its own chemicals section is not for assessing laboratory chemicals and reagents.

In Scotland and Northern Ireland, HTM 07-01 notes different colour-coding systems, and sites there should follow their own standard.

A few recurring items cause most of the difficulty. Sodium azide is present in many analyser reagents and kits at low concentration, and it can react with copper and lead in pipework to form explosive azides. That is one reason to identify what analyser waste contains and put the right classification and collection arrangements in place. Guanidine salts in nucleic acid extraction buffers can release toxic gas if they meet hypochlorite, so an extraction waste pot should never receive bleach.

Hypochlorite creates other problems at the autoclave. A bag of chlorine-treated waste placed in a steam autoclave can release chlorine gas, and solvents or volatile chemicals can be dangerous under heat and pressure. Materials containing chemical fixatives should stay out of the autoclave altogether, and those decisions belong in the lab's own risk assessment.

Fixed tissue is another point of confusion. GOV.UK lists chemically preserved anatomical waste as hazardous whether or not it is infectious, using 18 01 06* with the anatomical code, 18 01 02, or the infectious code, 18 01 03*. A pathology lab's retained specimens therefore do not belong in the same red container as unpreserved tissue. Our pathology and histology page goes into that stream in more detail.

Used absorbents and spill kits from chemical spills are classified under chapter 15 of the List of Waste, according to HTM 07-01. They are not clinical waste just because the spill took place in a clinical area.

Laboratories that autoclave have an extra route open to them. HTM 07-01 says that autoclaved laboratory wastes are considered offensive waste, so long as they do not contain chemicals. GOV.UK places sterilised laboratory waste in the healthcare offensive entries, 18 01 04 or 18 02 03. That can be a much better route for culture plates and consumables than incineration.

The condition matters, however. Validated autoclaving deals with the biological hazard, but it does not remove a chemical hazard. A plate with an antibiotic selection agent or an ethidium-stained gel raises its own question. Check the chemical content before a validated autoclave load is routed as offensive waste, and keep validation records that would stand up if your waste audit asked to see them. Containment level 3 work and any incident with a Hazard Group 3 or 4 organism has its own controls under COSHH, and RIDDOR can require reporting if a release could have caused severe illness. Those matters are beyond a collection, but they do affect what your waste paperwork should say.

A clinical waste container is also a transport package. GOV.UK's dangerous goods guide points to chapter 5 of HTM 07-01 for packaging and labelling of clinical waste, and says you must be registered as a waste carrier to carry it. Chemical waste needs compatible packaging according to its transport class. Keeping the chemicals in the right inner container and the clinical items in their approved container prevents most problems before the carrier sees them.

HTM 07-01 also asks for individual bags to be labelled or tagged, not just the carts holding them, because waste is often repackaged during transport. Laboratory waste from a shared hospital building is much easier to trace when each container shows the department it came from.

Non-hazardous laboratory streams move under a waste transfer note, while anything hazardous needs a consignment note. Where non-hazardous transfers repeat regularly, a season ticket can cover multiple transfers for up to a year, if the holder, carrier and waste type all stay the same. A hazardous note is issued for each movement.

Permitted sites in England and Wales must have a pre-acceptance audit before they can accept healthcare waste from you, and HTM 07-01 sets the frequency. Laboratories, dental practices and veterinary practices producing less than 5 tonnes of clinical waste a year fall on a two-yearly cycle. Sites producing 5 tonnes or more of clinical waste a year need one every 12 months. Other healthcare sites below that level need one every 5 years.

The audit describes your waste as it really is, so a change in assay, equipment or department may mean it needs revisiting. It is also a useful moment to check that nothing has drifted. A laboratory that began disposing of kits in orange because a new starter was shown the wrong bin will find it hard to spot from the paperwork. A walk through the lab with the audit in hand tends to find it quickly.