Ammonium perchlorate (CAS 7790-98-9): storage and disposal

Look at what stands within reach of the jar: a hot plate, a heated oven, a solvent bottle, a paper box or metal powder. Heat and contamination are the two ways explosive decomposition becomes possible, and in research labs both tend to creep up unnoticed on old stock. A shared shelf where the original owner has long gone is the typical finding. It belongs on its own, on non-combustible shelving in an oxidiser space, with flammable, acid, alkali, toxic and corrosive stock elsewhere. Quantity matters more than usual for this salt, so write down how much the label says is present. If you find it near heat or solvents, do not lift it or start to clear around it. Leave the area and make the enquiry first.

Age brings few visible changes. Sound stock stays a white crystalline solid, and it can look the same as new after a very long time, so a clean appearance should not reassure anyone. Damp from the air can make it clump, but the bigger question is contamination, which may not show. Look for any second colour, dust, paper fibres or metal specks inside the jar, staining on the shelf, a cracked container or a damaged cap. A faded label on an unknown white salt in a research store could be this, and that uncertainty matters by itself. If you see any of these, do not open or move the jar, and get a specialist assessment. No visual check can tell you how sensitive it has become.

This does not go through our standard collection route. It is arranged by manual enquiry, and never goes down the drain or into general waste.

It leaves only after a manual enquiry, and it may be a job for an explosives or emergency specialist instead of a chemical collection. It is not quoted online, and the online quote path does not accept it. A store assessment is recommended, with a competent chemist seeing it in person. Give the label wording, the amount the label states, the age if known, and everything within reach of it, especially heat sources and solvents. Do not open it, move it or try to make it safe. Keep people away if you have any doubt about its condition. It must never go into a sink, a drain, a bin or a skip. University stock normally takes code 16 05 06*, though that does not settle how it leaves.

Usually held as: legacy stock.

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.