Zinc chloride (CAS 7646-85-7): storage and disposal

Corrosive stock belongs low down, on a resistant tray, in a ventilated corrosive store. This solid draws water out of the air so readily that a loosely closed bottle will slowly turn into a damp mass, so the cap matters more here than for most salts. Keep it away from the solvent cabinet and from the oxidiser shelf, because a leak of corrosive stock can attack containers and a spill beside oxidisers can give off heat or fumes. In a histology room it should not sit at bench height beside fixatives or stains, where a splash would meet skin or eyes. Check that the cap lining is intact and that the tray beneath is dry, and record the date opened on the label.

A technician will see the crystals sticking to each other first. Zinc chloride is strongly water-attracting, so an old bottle often holds a solid cake, a paste or even a puddle of liquid at the base where the powder used to be. Look at the neck and cap for crusting and for corrosion of any metal liner, and at the shelf under the bottle for staining or a damp ring. Fumes on opening, a cracked bottle or a label that has peeled in the wet are all reasons to stop handling it. A once free-flowing solid that now needs chiselling out has changed condition, and it should be described that way on any paperwork.

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a corrosive other laboratory pack with compatible chemicals.

The code on the paperwork matters for this one. A laboratory pack uses 16 05 06*, while discarded inorganic chemical stock outside a laboratory pack is 16 05 07*, and a human healthcare setting such as a hospital histology lab uses 18 01 06*. Because it is classified as very toxic to aquatic life it must never go down a drain, and nobody should try to dry out or dilute a wet bottle before collection. Leave a caked or leaking container in a second sealed container on a tray, state on the record that it is damp, and book a specialist collection. UN 2331 applies to the carriage.

Usually held as: solid.

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.