Hydroxyethyl methacrylate (CAS 868-77-9): storage and disposal

One small bottle on a surgery shelf is easy to forget, so check the cap and the neck at the same time as the date. Methacrylate monomers are reactive liquids, and heat and light are the usual enemies, so keep the bottle in a cool cupboard away from the curing lamp, the sterilising unit and windows. In a dental store it should be kept apart from the cements and etchants so that a cap is not swapped. Because it may cause an allergic skin reaction, nobody should handle a leaking bottle bare-handed, and repeated small spills on a shelf are worth cleaning with care. Label it with the name and the date of receipt and keep it upright in a tray.

A clear, thin, colourless liquid is what a sound bottle holds. A monomer that is going off tends to thicken, turn syrupy, become cloudy or leave a rubbery film or gelled lumps in the neck and on the dropper. Those changes mean the liquid has started to set in the bottle. A warm bottle, one that feels soft or looks swollen, or a liquid that has set solid should not be opened. Beyond that, check for sticky residue on the cap, a perished dropper, faded labels and a missing date. Any bottle that has thickened or set should be listed for collection rather than being used up.

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.

Write the waste code and the form on the list together: 16 05 06* for a university lab, 18 01 06* in a human healthcare setting such as a dental surgery, and 16 05 08* where it is a discarded organic chemical outside a laboratory pack. Say whether it is neat monomer or part of an adhesive kit, and whether the liquid has thickened. Because it is a sensitiser, bottles with sticky threads are described as such. Leftover liquid does not go in a sink, in a clinical waste sharps bin or in the general bin, and nobody should try to cure or set it first. A registered carrier collects it.

Usually held as: neat, dental adhesive component.

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.