Lactose (CAS 63-42-3): storage and disposal

Most jars arrive as a fine powder in a plastic tub with a screw lid, and the lid is what protects it. Keep it in a dry, labelled, well organised store, away from damp walls, wash points and aqueous bottles, and dated on arrival. A pharmacy holder keeps it with other excipients and a stock record, and a pathology lab may hold it near culture media, so a clear label matters where several white powders sit together. Keep it apart from food grade supplies. After each use, wipe the thread dry before the lid goes back on.

Start with what looks normal: a loose, white, free flowing powder. What does not is lumping, a hard cake at the bottom of the tub, a sticky ring at the neck, any musty smell and spots of mould. Few signs specific to lactose appear beyond these damp effects, so the lid and label tell most of the story. In a busy pharmacy or pathology store, a jar opened often with a scoop that has been left inside is the likeliest to be contaminated. Record the condition, and do not scrape off the top layer to rescue the jar.

We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

Mixing it into ordinary kitchen waste or tipping the powder into a sink is not acceptable, since laboratory lactose stays a chemical waste. It is not normally classified as hazardous, so the non hazardous code 16 05 09 would normally apply, with 18 01 07 where a pathology or pharmacy setting counts as healthcare. A waste transfer note covers the movement. It is packed with other solid laboratory chemicals. Note the label wording, the container type, any caking and the approximate quantity. An expired pharmacy product is a different matter, so describe the stock for what it is.

Usually held as: solid.

Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.