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DIFFERENT CLASSES OF CHEMICALS:

• Organic chemicals

• Inorganic chemicals

• Flammable chemicals

• Toxic chemicals

• Oxidising chemicals

• Radioactive chemicals

• Explosive chemicals

• Corrosive chemicals

Many chemicals will be a combination of the above.

THE BASIC RULES:

1. When a chemical has more than one hazard associated with it, store it as the most dangerous hazard (e.g., if it is corrosive and flammable, store with flammables).

2. Separate the flammables from the oxidisers.

3. Flammables MUST be stored in an appropriate secure cabinet.

4. Oxidisers can be stored with general inorganic chemicals if they are not mixed with the organics. If inorganic and organic chemicals are stored together, oxidisers must be separated out and stored together as far away from organic as possible.

5. Keep the explosives separate and in a cabinet.

6. Keep large corrosives, e.g., conc acid stock bottles, close to the floor on spill trays where spillage will cause the least hazard.

7. Toxic chemicals can be stored on general shelves of the store if the store is secured.

8. Store radioactive chemicals according to regulation (in a secure cabinet fixed to the wall at least 2m from where people will be working).

9. If the store contains a flammables cupboard, then radioactive chemicals and gas cylinders cannot be stored here.

10. If the flammables cabinet is outside the store and there are no gas cylinders, then the radioactive cabinet can be inside the store (if legal requirements are adhered to).

11. Some chemicals should only be made when needed and disposed of as soon as possible after the practical (e.g., Tollens reagent (silver mirror test); chlorine water: the chlorine will leak from the container).

12. You should have an up-to-date stock list and a risk assessment that covers the use of the storeroom.

SPECIAL CASES:

Sodium, potassium, and lithium metals: These are stored under oil and will be delivered as such. Make sure the oil levels are maintained and that any small pieces of metal remain under the oil. If potassium metal shows signs of yellow crusting it should be disposed of (contact CLEAPSS/SSERC for guidance).

Silicon chloride: once opened the bottle can seal itself (formation of silicon dioxide when silicon chloride is in contact with water in the air) and has the potential to explode in very hot weather. Store inside a secondary container containing a desiccant.

White phosphorous: store under water (change water regularly). Store with Toxic chemicals; keep apart from oxidisers, sodium, potassium.

Bromine liquid: Store inside a secondary container with silica gel. Store with a bottle of 1 M sodium carbonate solution (note guidance has changed from sodium thiosulfate solution), and solid sodium carbonate (hydrated) both in case of spills.

Mercury: Keep in a secondary bottle, in a tray. Keep a mercury spills kit alongside. 2,4-dinitrophenylhydrazine: explosive when dry. After opening this should be stored inside a secondary container on wet sand (or similar) and should be checked regularly. The stock bottle may need to be put into a clear bag to stop the label getting wet)

This is by no means an exhaustive list.

For more detailed information and guidance, visit the CLEAPSS/SSERC websites.