The distillation of coal tar yields a variety of compounds, three of which are notably toxic: cresols (phenolic compounds), crude creosote (composed of cresols, heavy oils, and anthracene), and pitch. Tars are also produced from crude petroleum or wood. Creosote contains less volatile liquid and solid aromatic hydrocarbons of coal tar and some phenols. They have been used for restricted applications as wood preservatives. Cresols, composed mainly of hydroxytoluenes, are used in soaps and disinfectants. Coal-tar and pine-tar pitch are the brown to black, amorphous, polynuclear hydrocarbon residues left after coal tar is redistilled. Access of animals to coal tars is often by direct chewing on or consumption of product, rather than inclusion in feed or water. Clay pigeons (older products), tar paper, creosote-treated wood, and bitumen-based flooring are typical sources.
