Chemical industry, complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives.

Although the chemical industry may be described simply as the industry that uses chemistry and manufactures chemicals, this definition is not altogether satisfactory because it leaves open the question of what is a chemical. Definitions adopted for statistical economic purposes vary from country to country.

Also the Standard International Trade Classification, published by the United Nations, includes explosives and pyrotechnic products as part of its chemicals section. But the classification does not include the man-made fibres, although the preparation of the raw materials for such fibres is as chemical as any branch of manufacture could be.