Cholesterol (CAS 57-88-5): storage and disposal

A practical check at the shelf is the label, because this name appears on radiolabelled products too. Stock described as tritiated or marked (3H) is radioactive material, so it stays where it is, labelled, with its record, and goes to the Radiation Protection Adviser. Ordinary cholesterol sits in a tightly closed jar on a general shelf in a dry store. It is oily to the touch and dusty when disturbed, so keep it away from open food and from damp areas. Date it on arrival. Biology prep rooms often keep it alongside other lipids and stains, which is fine, but keep it out of the food science cupboard even if the powder looks like a kitchen ingredient.

Normal cholesterol is white to pale cream, waxy and slightly flaky. What does not look right is a yellow or tan tinge, particularly on the surface of the flakes. Cholesterol reacts slowly with oxygen from air, so an old jar left open or half full will yellow, develop a stale oily smell and may clump. A greasy film inside the cap, a faded label and flakes that have stuck into a hard lump are further signs. None of these makes the jar dangerous by itself, but the colour change tells you the stock is no longer pure, and an undated jar cannot be described properly to a collector.

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.

Start the record with the container, not the chemical: the label wording, the form, the approximate amount and whether anything on it mentions a radioactive isotope. If it does, stop and go to the Radiation Protection Adviser, as it falls outside a chemical collection. Ordinary cholesterol is not classified as hazardous on the sources we checked, so the waste transfer note applies, but it is still a chemical waste and not general rubbish. Jars are packed with other compatible organic solids for specialist collection. It does not go into the household bin or a laboratory sink, and nobody should try to melt it down or clean the jar out first.

Usually held as: solid.

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.