Benzyl alcohol (CAS 100-51-6): storage and disposal

Read the dates first when you reach the shelf: an opened bottle is due a review at 12 months, and one with no date is already a question. A close-fitting cap matters more here than on many reagents, because air drives the slow oxidation, and a part-used bottle holds more of it. Store it dry and labelled, with oxidisers kept well away. Pharmacy stock needs its own place, apart from laboratory reagents and anything food grade, so the two grades never get confused. Because it can sensitise skin, a sticky shoulder or cap deserves attention: a bottle in that state should not be picked up with bare hands, and repeated small contact is what catches people out with an allergic reaction.

Labels and caps tell the first part of the story: a faded label, a stained cap or a failed seal all point to long storage. Inside the bottle, benzyl alcohol slowly oxidises to benzaldehyde, so old stock picks up an almond smell, and you may notice it near the shelf if the seal is poor. Nobody should open a bottle or sniff it to check. Benzaldehyde itself goes on to oxidise to benzoic acid, so white crystals at the neck could simply be that, but peroxides cannot be ruled out, and that is not something to judge by eye. If the bottle is old, undated or shows warning signs, do not move it, do not open it, and get a specialist assessment. Peroxide testing is for competent staff only.

This can form peroxides as it ages, especially after opening. Age and the opened date matter more than appearance, so a container with no opened date should be treated as old.

Review after 12 months: Review interval after opening from the cited peroxide former lists, not an expiry date from a manufacturer. Class C and all other chemicals are left null.

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.

However small the pharmacy remainder, it must never go into a sink, a drain, a general waste bin or a skip, and nobody should try to treat it first. Its familiar place in medicines can make it look like an everyday item, yet it remains a hazardous waste with specialist collection as the only route. The code depends on where it is held: 16 05 06* is usual for laboratory stock, 16 05 08* covers a discarded organic chemical outside a lab pack, and 18 01 06* applies in a human healthcare setting. So tell the collection team which setting it came from, along with grade, bottle sizes and any opening date. Any almond smell or crystals around the neck should go on the list too, as they affect how the bottle is assessed.

Usually held as: neat.

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.