The ceramics industry undertakes many tasks that produce fine clay dust, which contains particles of free silica that can be harmful to one’s health. Potters and workers in brick factories are among those who may be exposed. Silica, especially recently fractured particles, can be acutely toxic by forming silicic acid in the lungs, causing tissue damage. Over the long term, fine particles can accumulate in the lungs, causing the well-known occupational disease silicosis.

Clay dust is best removed at source, since ventilation systems are likely to draw a large amount of dust through air that is to be breathed. Workers should be positioned upstream in the airflow from the production of dust to the extraction unit, and a sufficient airflow volume to remove the dust should be ensured. It is recommended that clays with more than 1% free silica be treated as very toxic, while clays with less silica can be regarded as nuisance dusts.

Clay dust extraction equipment usually needs to be specially designed. Instead of simply exhausting the dust, fabric filters are usually used in order to prevent dust problems in other areas. HEPA filters may be needed because the particles are very fine. In addition, the moisture content of clay can become a problem. When the conveying air temperature is at or near the dew point, the particles will become sticky on the surface. These particles will then stick to the walls of the baghouse or ducting, which can eventually lead to plugging. Temperature and humidity control equipment and proper placement can help to prevent these problems.