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
Coal tar benzofluoranthenes, perylene, 6-rings: dibenzopyrenes, dibenzofluoranthenes, benzoperylenes, 7-rings: coronene), as well as methylated and polymethylated derivatives, mono- and polyhydroxylated derivatives, and heterocyclic compounds. Others include benzene, toluene, xylenes, cumenes, coumarone, indene, benzofuran, naphthalene and methyl-naphthalenes, acenaphthene, fluorene, phenol, cresols, pyridine, picolines, phenanthracene, carbazole, quinolines, fluoranthene. Many of these constituents are known carcinogens. Various phenolic coal tar derivatives have analgesic (pain-killer) properties. These included acetanilide, phenacetin, and paracetamol (acetaminophen). Paracetamol is the only coal-tar derived analgesic still in use today, but industrial phenol is now usually synthesized from crude oil rather than coal tar. Exposure to coal tar pitch volatiles can occur