Creosote mixed with coal-tar creosote, or fortified with pentachlorophenol. Water-gas-tar creosote is also derived from petroleum oil or shale oil, but by a different process; its distilled during the production of water gas. The tar is a by-product resulting from enrichment of water gas with gases produced by thermal decomposition of petroleum. Of the creosotes derived from oil, it is practically the only one used for wood preservation. It has the same degree of solubility as coal-tar creosote and is easy to impregnate into wood. Like standard oil-tar creosote, it has a low amount of tar acids and tar bases, and
Pyrobitumen thermal exposure, the bitumen continues to evolve and disproportionates into pyrobitumen and more oil and gas. The terms bitumen and asphalt are often used interchangeably to describe highly viscous to solid forms of petroleum that have been used in construction since the fifth millennium B.C. Bitumen is distinct from tar, which properly describes a product formed by pyrolysis (destructive distillation) of coal or wood. Pitch recovered from petroleum by distillation is also sometimes called bitumen or asphalt. The expression "bitumen" originated in the Sanskrit, where we find the words jatu, meaning "pitch," and jatu-krit, meaning "pitch creating", "pitch producing" (referring