Diethyl ether: safe storage and disposal

For new stock, hold the smallest amount your work needs, in the supplier's container, in a fire-resisting cabinet. Keep it away from heat, light and any ignition source. Its vapour is heavier than air and it ignites readily, so a hot plate or a spark several metres away can be enough. Your DSEAR assessment should reflect this.

Date every container twice: once on arrival and once on first opening. Published peroxide former lists give a review interval of twelve months from opening. This is a point at which someone must make a decision, and it is not a supplier's expiry date. Make sure your register shows both dates, and that someone owns the review. Close containers firmly after use, and do not hold part-empty bottles for long, as air in the headspace feeds the reaction.

Refrigerate only in a unit designed for flammable materials. Domestic fridges have ignition sources inside them.

Read these signs without picking up the bottle.

• Crystals or a crust around the cap or neck
• Crystals, a solid, a cloudy suspension or a viscous layer in the liquid
• A rusted or swollen cap, or a tin with a corroded seam
• No dates at all, or dates long past the review interval
• A very old label, an older anaesthetic grade or a supplier name no longer trading
• A liquid level much lower than expected, which suggests a part-used bottle with plenty of air above it

Absence of any sign does not clear a bottle. Peroxides can form with nothing visible, especially in metal tins and dark glass. We give no home testing advice, because opening the container is itself the risk. Peroxide testing, if it happens, is for a specialist to do after deciding the container can be opened at all.

Forms explosive peroxides on exposure to air and light, which can crystallise around the cap.

This can form peroxides as it ages, especially after opening. Age and the opened date matter more than appearance, so a container with no opened date should be treated as old.

Review after 12 months: Review interval after opening from the cited peroxide former lists, not an expiry date from a manufacturer. Class C and all other chemicals are left null.

Old or undated ether does not go by routine collection. We handle it as a manual enquiry, with a chemical store assessment first. The reason is simple: nobody can judge the age and state of a bottle from a line on a list. Where the risk is high and cannot wait, that becomes a job for emergency chemical removal.

Do not evaporate it, pour it away or add anything to it. Do not transfer it to a different bottle. Any of those actions could trigger an accident.

The solvents entry 20 01 13* belongs to municipal collections and is not the normal code for a laboratory collection. For transport, diethyl ether is UN 1155, packing group I.

School and college stores may hold one small bottle, or an old tin. Pathology and university labs may hold more, with regular research stock in small containers. Legacy finds are common in older hospital stores, because ether was once a routine anaesthetic. A department that has been closed or moved may reveal it years later.

Usually held as: neat, legacy anaesthetic.

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.