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
Birch tar is an effective repellent of gastropods. The repellent effect lasts about two weeks. The repellent effect of birch tar oil mixed with petroleum jelly applied to a fence lasts up to several months. Birch tar oil is also used in perfumery as a base note to impart leather, tar, smoky, and wintergreen notes. Birch tar Birch tar or birch pitch is a substance (liquid when heated) derived from the dry distillation of the bark of the birch tree. It is composed of phenols such as guaiacol, cresol, xylenol and creosol. Birch tar was used widely as an adhesive as early