Expired and unlabelled chemical disposal

Out of date stock is by far the larger share of this work, and most of it is straightforward once listed. We deal with:

• expired reagents and teaching chemicals in sound, labelled containers
• bottles with a damaged, faded or handwritten label
• decanted and reused containers whose contents are in some doubt
• bottles with no label at all, where a location or history gives some clue
• legacy stores from closed departments, retired staff or building moves
• reagent kits and part-used products with no safety data sheet to hand

Some stock moves straight to a manual enquiry. That means anything showing signs of instability, along with explosives, radioactive materials, controlled drugs, gas cylinders and asbestos. Unknown substances that cannot be placed with confidence join them, and the first step is usually a chemical store assessment.

• a list of labelled stock, split into sound containers and those with concerns
• a separate list of unknowns, with location, container type, size and appearance
• photographs of any concerning items, taken without moving them
• any old stock lists, purchase records or staff names that might help
• the site's access details, and the person responsible for the room
• a description of the store's conditions, including ventilation and any heat or damp

Honesty about what you do not know is the most useful thing you can provide. It lets the carrier bring the right containers and a chemist who is expecting the job, and it keeps your staff away from the bottles that need the most care.

Manufacturers' dates are mostly about purity. A bottle of copper sulfate five years past its date is usually still copper sulfate, and its only problem is that nobody wants it. A research reagent with a two-year date may have lost its potency, which matters for the experiment but not for the waste.

A second group of chemicals gets more dangerous as it ages, and their dates can mislead you. Ethers and some other solvents form peroxides over time, and faster once opened because air gets in. Both the date received and the date opened matter. Picric acid and 2,4-DNPH become far more dangerous if they dry out. The DfE guidance for schools singles them out, and also warns that some substances can decay over time and present a hazard. Concentrated hydrogen peroxide vents gas as it decomposes, and old alkali metals can develop dangerous surface layers.

So do not sort your store by date alone. Sort it by what the chemical is, how long it has been open and what the container looks like.

A short visual check, carried out without touching, can pick up warning signs, though some deterioration does not show. Look for crystals around the cap or neck, a solid lump in what should be a liquid, or a liquid that has separated into layers. Look for a bulging or sucked-in container, rust or corrosion on a metal lid, staining on the shelf below or a cap that has been eaten away.

Container age matters too. Pre-metric pack sizes, glass-stoppered bottles and old-style orange hazard labels are signs of a very old store. Stock from before 1990 needs more caution, because the closure may be as much of a risk as the contents.

If you see any of these, stop there. Do not unscrew, shake, tilt or carry the bottle to better light. Note where it is, keep the store secure and tell us what you can see. If you believe there is an immediate danger of fire, explosion or toxic release, clear the area and call the emergency services.

Good identification starts with paperwork and people, long before anyone opens a bottle. Old stock lists, purchase records and lab notebooks often settle the question. So does the neighbouring shelf, since a store organised by a careful person will usually be consistent. Ask whoever worked there before, including anyone who has retired. Then write down where the bottle was found, how large it is, what it looks like and what you think it might be. Your own confidence counts, as long as it is recorded as an opinion.

A photograph of the container taken from a safe position helps a chemist form a view without a visit. Some items can then be listed with reasonable confidence. Others will need the chemist to look in person, and in a few cases a small sample will be taken and analysed. That is specialist work, and it is not something to try with pH strips at the bench.

Reused bottles are the classic trap. A Winchester labelled ethanol may hold a teaching solution that was decanted years ago. Bottles in a hospital store may have been relabelled in a ward's own shorthand. Treat a label as evidence, not proof.

Not knowing what something is does not take it outside the rules. You must classify waste before it is collected, and the paperwork needs a description, the code and the substances present. WM3 says a mirror entry waste whose composition is not known and genuinely cannot be determined must be classified under the hazardous entry. It also says that direct testing cannot be used to classify a waste of unknown composition as non-hazardous.

Bulking up unknowns is also not allowed. GOV.UK's mixing guidance prohibits mixing that hides the identity of a waste, and combining several half-bottles of unknown liquids could also start a reaction. A single unknown stays a single line on the list.

Medicines add a further wrinkle. A product does not stop being a medicine because the label has come off, and HTM 07-01 requires cytotoxic and other medicines to be kept apart. Unlabelled vials in a hospital or a vet's cupboard should be treated with that in mind, and flagged to the responsible pharmacist or clinician.

The biggest backlogs follow organisational change. A school's science block is rebuilt and a locked cupboard reappears. A hospital consolidates its pathology service and leaves one site's store behind. A research group disbands and nobody claims its cold room. In each case, the people who know the stock have gone, and the chemicals have been left without an owner.

The first job is to give the room an owner again. Lock it, name a responsible person and record what you can see from the door. The employer's duties under COSHH do not pause because a department has closed, and neither does the need to keep track of hazardous substances. Priority goes to anything that could be degrading, in a store that may be hot, damp or unventilated. Next, decide whether the job should start with a list or with a chemist's visit. If you have more than a handful of unknowns, or anything from the warning signs above, start with the visit.