Creosote from both oil shale and petroleum, and are known as oil-tar creosote when derived from oil tar, and as water-gas-tar creosote when derived from the tar of water gas. Creosote also has been made from pre-coal formations such as lignite, yielding lignite-tar creosote, and peat, yielding peat-tar creosote. The term creosote has a broad range of definitions depending on the origin of the coal tar oil and end use of the material. With respect to wood preservatives, the United States Environmental Protection Agency (EPA) considers the term creosote to mean a pesticide for use as a wood preservative meeting the
Cedar oil was laid in natrum or natron—a fixed alkali—for the prescribed period, after which the cedarwood oil, which had dissolved the soft organs, was released; and the body, its flesh dissolved by the natron, was reduced to preserved skin and bones. Until the development of synthetic immersion oil in the 1940s, cedarwood oil was widely used for the oil immersion objective in light microscopy. It is still sometimes also used to clarify emeralds. Cedar leaf oil from "Cedrus atlantica" does not contain thujone. Cedarwood oil is a mixture of organic compounds considered generally safe by the FDA as a food additive