Sodium dichloroisocyanurate (CAS 2893-78-9): storage and disposal

In a school prep room the tub of tablets is often kept with cleaning supplies under a bench, within reach of the acid descaler and the ammonia based spray. That is exactly the combination to avoid: acids and ammonia must never share space with it, nor must solvents such as acetone. Sound stock belongs in the oxidiser space on non-combustible shelving, in its original closed container protected from moisture. Do not attempt to tighten or open a container showing signs of decomposition. Separate it from flammable, alkali, toxic and corrosive stock too. Clinics, dental practices and veterinary rooms that hold tablets for surface disinfection should do the same, and avoid decanting loose tablets into unmarked pots.

Moisture is the thing that changes this substance. Tablets that have crumbled, swollen, stuck together or taken on a damp, chalky look have been exposed to air, and a sharp chlorine smell around the container may indicate decomposition or a reaction involving moisture or incompatible material. Granules clump into a hard cake. Nearby metal tends to suffer first: look for corroded caps, rust spots on the shelf, stained or lifting labels and a crust around the neck of the tub. A tub that has been topped up from several others, or has lost its label, should be recorded as it is found. If a strong chlorine smell is present, do not approach or handle the tub. Keep people away from the affected area and request specialist safety assistance.

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

Never combine leftover tablets with acids or ammonia products, and none of it goes into a sink, a drain, a general waste bin or a skip. Staff should not try to treat or dissolve it first. UN 2465 is the transport number and 16 05 06* the usual waste code, with 18 01 06* for a clinic or dental surgery and 18 02 05* for a veterinary practice. It is packed in an oxidiser group in a lab pack, away from acids, ammonia and flammable stock. Record whether the stock is tablets or granules, how many tubs there are, and whether any have crumbled or smell of chlorine.

Usually held as: tablets, granules.

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.