BaSO4 is commonly known as barite. It is a heavy metal salt. We know that heavy metal salts are toxic. However, because BaSO4 is neither soluble in water nor soluble in acid, it is impossible to produce toxic Ba2+ even if we eat it in the stomach, so it is non-toxic. We sometimes use it when we go to the hospital for X-rays, called "barium meal", for imaging. Barium sulfate, the main component of barite, is not easily soluble in water. Although it is non-toxic, it can cause chest pain or cough after being inhaled by the human body, and it can also stimulate the eyes to a certain extent. If people breathe it for a long time, it may cause barium pneumoconiosis. As for the environment, it will cause atmospheric pollution.