Chemical industry includes those industries involved in the production of petrochemicals, agrochemicals, pharmaceuticals, polymers, paints, oleochemicals etc. Chemical processes are used, including chemical reactions to form new substances, separations based on properties such as solubility or ionic charge , and distillations, in addition to transformations by heating and other methods.

Chemical industries involve the processing of, or change in, raw materials obtained by mining, and agriculture among other supply sources, into materials and substances that are useful on their own, or in other industries. The food-processing industries are generally not included in the term "chemical industry".