Solution

The feeling of dread when reaching into a communal lab coat pocket will be a familiar one to most chemists. Sweaty gloves, pipette teats and spatulas are all common inhabitants but provoke very different responses. The critical question on the vial of mystery powder is whether or not any of the contents has spread onto the visitor whether by a loose cap or a dirty vial. If so, she should wash her hands. Efforts should be made to deduce the vial’s most likely contents by asking those working in the lab. If there are any adverse reactions or other concerns, the visitor should seek medical advice. Good labelling practice would have prevented this happening in the first place.

Charles Harrison is a safety adviser at a UK university