What to do with unlabelled bottles in a lab

Do and do not, at the shelf

The instinct to tidy is what you are resisting. Many unlabelled bottles are dull: an old buffer, a decanted solvent, tap water somebody meant to throw out. But the small number that are not dull look much the same, and a few become more sensitive with age. Old diethyl ether can carry peroxide crystals at the cap, and turning that cap is the hazard. Dried picric acid is sensitive to shock and friction, including at the closure. You cannot tell by looking from across a room, so you treat them all alike.

In a school prep room

Labels go missing in school stores for familiar reasons. Paper labels fail after decades in acid fumes. Teaching solutions get decanted into a spare bottle for a lesson and never relabelled. A jar from a retired colleague's demonstration kit sits for years behind newer stock.

So your investigation is mostly historical. Who has worked here, and what practicals did they run? Is there an old stock book or a previous inventory, even a paper one? Does the bottle sit in a group, such as among metals or indicators, that hints at its contents? Your advisory service can help with interpretation, which will be CLEAPSS for most schools or SSERC in Scotland. Keep all of this on paper. It helps the specialist, and nothing about it requires touching the bottle.

Check also what lies nearby. A leaking unlabelled bottle above a shelf of acids is a different problem to a sound one alone in a cupboard. If you cannot safely make the area secure, close the room and escalate. In a school, that means keeping pupils out, and that can mean rearranging a lesson today rather than discussing it next week.

In a hospital or pathology store

Hospital stores produce a different type of unknown. There may be a specimen pot with a preservative no longer on the request form, a staining reagent aliquoted years ago with the abbreviation only the old lab understood, or a bottle in a closed department after a reorganisation. Decanted fixatives are a particular concern, because some histology fixatives contain picric acid and a yellow stain on a shelf can matter.

Your starting points are different too. Ask the laboratory manager, the department's quality records and your standard operating procedures. Old SOPs often name the reagents in use at a given date. Check with the trust's waste officer, who will need to know how the bottle will be coded. Waste chemicals must stay out of clinical and offensive streams under HTM 07-01, so an unknown does not go in the yellow bag to make it disappear. The healthcare waste classification guidance reserves that bag for items that are both infectious and chemically contaminated.

If a sample may be infectious as well as chemically unknown, say so straight away. It changes who can safely handle it.

What to record about an unlabelled bottle

Write down what you can see from where you stand. A photograph taken without moving anything is valuable, and so is a second one showing the shelf around it.

• Location: building, room, cabinet and shelf
• Container: glass or plastic, colour, cap type and approximate size
• Contents as seen: liquid or solid, colour, level, and any layers
• Condition: crystals, crust, staining, bulging, corrosion or leaks
• Remnants of any label: a fragment of a name, a date, a supplier
• What surrounds it, and whether anything on that shelf is incompatible
• Who found it and when, with any history your colleagues can offer

How unknown chemical identification works

Identification runs from the least invasive method to the most. First comes the paper evidence you have gathered. A specialist then looks at the bottle in place, judging whether it is stable enough to handle at all. Those two steps resolve many bottles, at least as far as a hazard group, which is often all that safe packing needs.

Anything further is a matter for trained people with the right equipment. That may be a small sample for analysis, carried out once the container has been judged safe to open. Some containers are never opened: if the assessment finds the risk too high, the bottle goes forward for specialist removal as it stands, with arrangements made to suit.

Do not expect every bottle to get a name. The aim is to know enough to move it safely and to describe it honestly. Where the composition genuinely cannot be established, WM3 says it must take the hazardous code, and adds that direct testing cannot show an unknown waste is non-hazardous. In England that leaves no room for a cheaper code on a guess.

Be open about this on the paperwork. A description reading "unidentified liquid, approximately 500ml, in sealed brown glass" is honest, and it tells the receiving site what it is dealing with.

Stopping the next unlabelled bottle

Unknowns begin as decisions that seemed harmless. Label decants at the moment you pour them, with name, date and initials, and do it before the bottle leaves your hand. Replace a failing label while you can still read it. Check the labels themselves during your stock check, as well as the names on your list. Make leavers hand over their shelves.

Then keep emergency information current. HSE advises thinking about how you would give information to the emergency services, and a list that says "two unidentified bottles, cabinet 3" is worth much more to a crew than silence.

Where you have one or several bottles you cannot place, a chemical store assessment gives you a specialist's view of the whole store before anything moves.