Coal tar the European Chemicals Agency. The exact mechanism of action is unknown. Coal tar is a complex mixture of phenols, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic compounds. It is a keratolytic agent, which reduces the growth rate of skin cells and softens the skin's keratin. Coal tar is produced through thermal destruction (pyrolysis) of coal. Its composition varies with the process and type of coal used – lignite, bituminous or anthracite. Coal tar contains approximately 10,000 chemicals, of which only about 50% have been identified. Components include polycyclic aromatic hydrocarbons (4-rings: chrysene, fluoranthene, pyrene, triphenylene, naphthacene, benzanthracene, 5-rings: picene, benzo[a]pyrene, benzo[e]pyrene,
Carbon, Iowa originally named Walters, after its first settler, but was renamed Carbon after the discovery of coal. The town was established in 1873, but was not incorporated until 1903. A post office was established in Carbon in 1874, but from 1877 to 1880, the name was changed to Shinn. By the time of the Civil War, there were small coal mines along the riverbanks near Carbon. In 1894, there were 9 coal mines in Carbon, of which 5 were in current use. Typical mine shafts were 80 feet deep, working a coal seam 12 to 20 inches (30 to 50 cm)