Benzaldehyde (CAS 100-52-7): storage and disposal

Stock sits in general storage, in a dry, labelled, well organised store, and should be dated on arrival. The habit that does the damage is leaving the cap loose or opening the bottle often, because the liquid slowly takes up oxygen from the air. Keep the cap tight, store it away from heat and direct light, and avoid decanting into small unlabelled containers. Keep it apart from food grade supplies if the cupboard is shared. A technician checking a prep room can look at the neck of the bottle first, since that is where changes appear before the rest of the liquid is affected.

The sign most technicians will meet is white crystals around the cap, on the thread or in the liquid. That is benzoic acid, which forms as benzaldehyde reacts slowly with oxygen in the air, and a bottle with a crust or a layer of solid has been exposed for a long time. The liquid may also look more yellow than a fresh bottle. A crusted cap can seize, so do not force it. Look at the label for fading, the level against the stock record, and the glass for cracks. The crystals alone are not an emergency, but the bottle should be listed as aged stock and not used.

We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a general laboratory pack with compatible chemicals.

It goes into a lab pack with other compatible organic liquids and is usually described under waste code 16 05 06*, or 16 05 08* for a discarded organic chemical outside a pack. Put on the record whether crystals are present and whether the cap is crusted, since the collector handles a seized cap differently from a clean one. Include bottle size, approximate fill and the date of receipt if known. It is classed as harmful if swallowed, and it is never emptied into a sink or into the bin, and nobody should try to filter off or treat the crystals.

Usually held as: neat.

Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.