All containers must be labelled unless you know what they are by smell.

The statement suggests that all containers must be labeled unless their contents can be identified by smell. However, it is essential to understand that labeling containers serves critical safety and regulatory purposes. Proper labeling helps to ensure that anyone handling the materials knows exactly what substances they are dealing with, which is crucial in a salon or spa environment where various chemicals are used. Relying solely on smell could lead to dangerous situations, including potential allergic reactions or chemical burns, as some substances might have similar odors.

Labeling is a fundamental aspect of workplace safety to prevent misuse or accidents. While some may argue that familiar scents can identify chemicals, such an approach is not reliable and poses significant risks. Thus, it is not true that containers can be unlabelled based solely on one's ability to identify them by smell. The assumption that one can always accurately discern a substance by its smell is flawed and unsafe, reinforcing the necessity for clear labeling of all containers in a professional setting.