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,
Coal breaker more marketable product. Here, a series of interlocking, toothed crushers or rollers would break lump coal into progressively smaller sizes. On the fourth level down, the coal was further cleaned of impurities. This was originally done primarily by hand, but hand picking was gradually supplanted after 1910 by improved screens and jigs. Although breaker boys worked at all levels of the coal breaker, most of the removal of impurities by hand occurred on this level. (Some picking did occur on the ground level of the coal breaker, where boys would locate good pieces of coal in the culm and return