The chemical industry comprises the companies and other organizations that develop and produce industrial, specialty and other chemicals. Central to the modern world economy, it converts raw materials into commodity chemicals for industrial and consumer products. It includes industries for petrochemicals such as polymers for plastics and synthetic fibers; inorganic chemicals such as acids and alkalis; agricultural chemicals such as fertilizers, pesticides and herbicides; and other categories such as industrial gases, speciality chemicals and pharmaceuticals.

Coal gas is a flammable gaseous fuel made from coal and supplied to the user via a piped distribution system. It is produced when coal is heated strongly in the absence of air. Town gas is a more general term referring to manufactured gaseous fuels produced for sale to consumers and municipalities.