Potassium thiocyanate (CAS 333-20-0): storage and disposal

Harm by three routes, swallowing, skin contact and inhalation, together with serious eye damage, decides how it is handled: eye protection, gloves and a lid that goes back on straight away. Keep it away from acids, which can release toxic gas from a thiocyanate, and away from anything it could be confused with on a shelf of white salts. A dry, labelled, well organised store is the baseline. School and college stores that kept it for the iron test should check that a tub from years ago still has a readable label and a date of receipt.

It takes up water from the air, so the first sign on old stock is crystals that have clumped, turned wet or run together into a damp mass at the base. A tub left open may hold a pool of liquid, with a sticky crust at the neck and a stained label. The salt gives few other distinctive signs, so also check for a cracked tub, corroded cap, faded writing and a missing date. A wet tub is harder to handle safely and should be recorded as damp, and reported, instead of being dried or emptied.

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.

A pathology store in human healthcare would use 18 01 06*, while a school or university holder would use 16 05 06*, or 16 05 07* for a discarded inorganic chemical outside a lab pack. Acids are kept out of the same box, for the reason they are kept off the shelf. It is never poured into a sink or drain or put in general waste or a skip, and staff should not try to dry or treat it. Record the container size, how much is left, and whether the contents have gone wet or run into liquid.

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.