Inhalation of large quantities of China clay powder is moderately hazardous, causing kaolinosis, a disease in which the lungs becomes mechanically clogged by the clay. China clay may also cause silicosis if it contains free silica. Asbestos is highly toxic by inhalation and possibly by ingestion. It may cause asbestosis, lung cancer, mesothelioma, stomach cancer and intestinal cancer. Talcs are often contaminated with asbestos.
Respiratory problems can also result from inhalation of powders that develop when aged clay dries.
The molds, which can contribute to the workability of the clay, can cause skin problems, particularly if there is a pre-existing dermatitis. Handling cold wet clay, such as when throwing clay, can cause abrasion and drying of the hands, particularly the fingertips. This is a result of the mechanical friction or rubbing of the clay particles on the hands, the oil absorbing ability of the clay, and the harmful effects from prolonged exposure to cold water. The use of a kickwheel for throwing clay is a mechanical hazard since the moving parts can cause cuts and abrasions, particularly with children. Small pieces of wet clay that collect on the floor and bench can dry and becomes pulverized, producing an inhalation hazard due to the presence of free silica.