Carbon black [C.A.S. No. 1333-86-4] is virtually pure elemental carbon in the form of colloidal particles that are produced by partial combustion or thermal decomposition of gaseous or liquid hydrocarbons under controlled conditions. Its physical appearance is that of a black, finely divided pellet or powder. Its use in tires, rubber and plastic products, printing inks, and coatings is related to properties of specific surface area, particle size and structure, conductivity, and color. Approximately 90% of carbon black is used in rubber applications, with the remainder used as an essential ingredient in hundreds of diverse appli- cations, such as plastics, pigments, and coatings.