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Most creosote is produced from the distillates of coal tar, which is heated at successively higher temperatures to yield several medium distillates (naphthalene oils, middle oils, creosote oils, wash oils, anthracene oils, and heavy oils). Coal tar creosote is a blend of these oils (SCA 1994).
Ninety-seven percent of the creosote produced is used as a wood preservative and water proofing agent (ATSDR 2002). Micklewright (1998) estimated that about 230,000 tons of creosote preservative was used in the United States in 1997. Creosote may be applied to wood using pressure, dipping, deluging, or spraying. Wood products treated with creosote include telephone and other poles, railroad ties, pier and bridge decking and piles, home fencing, and playground equipment.
The EPA Toxics Release Inventory reports that 54,716 pounds of creosote was disposed of in 73 RCRA Subtitle C facilities, 352,724 pounds were lost to the air, and 5,374 pounds were discharged to surface waters in 2005. The National Priorities List contains at least 28 wood treating sites that used creosote.
The uncontrolled incineration of coal tar creosote-treated wood can release polycyclic aromatic hydrocarbons, halogenated dioxins, and furans into the air. Thus, the International Programme on Chemical Safety warns against burning treated wood. These compounds may also be released into the atmosphere on hot days when soluble creosote components evaporate directly from the surface of treated wood.
Marine pilings infused with creosote as a means of controlling animal and plant growth can leach creosote into adjacent soil and water supplies. Surface water also can be contaminated when spills, such as the one near Slidell, Louisiana, occur while transporting creosote waste on barges. Compounds in creosote not only accumulate in sediment, but also in organisms. In some cases, advisories have been issued against eating fish and shellfish contaminated with high levels of creosote compounds.
Before stringent environmental regulations were enacted in the mid-1980s, companies producing or using creosote typically built unlined, onsite creosote waste lagoons. Creosote could easily leach from these lagoons to the ground water. However, unless the soil is very porous, creosote rarely reaches the ground water because it is quite viscous. Nevertheless, even in fine-grained soils, small amounts of the soluble constituents of creosote can reach the ground water leading to bad tasting, greasy, and odorous water. An example of a site with soil and ground water contaminated with creosote is the Wyckoff/Eagle Harbor Superfund site, which is an 85-year old wood treatment facility that is undergoing cleanup (Superfund Fact Sheet).
For Further Information
Wood Preservation Statistics: 1997, A Report to the Wood Preserving Industry in the United States
Micklewright J. 1998.
American Wood-Preservers' Association, Selma, AL
Swedish Chemicals Agency (SCA), 1994.
This creosote summary, which was developed for media company inspectors, describes the manufacturing of creosote and creosote uses.
Toxicological Profile for Wood Creosote, Coal Tar Creosote, Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles
Agency for Toxic Substances and Disease Registry (ATSDR)
U.S. Department Of Health And Human Services, 2002, 394 pp
This profile covers coal tar creosote human health effects, chemical and physical properties, manufacturing volume data, potential for human exposure (environmental fate and transport), and analytical methods.
Superfund Fact Sheet: Wyckoff/Eagle Harbor Site, Bainbridge Island, Washington
U.S. Environmental Protection Agency (U.S. EPA), 1998, 6 pp
This fact sheet summarizes site background information, the groundwater cleanup strategy for the site, and cleanup progress during 1997.
Concise International Chemical Assessment Document (#62) Coal Tar Creosote
International Programme on Chemical Safety (IPCS), 2004
This document is a comprehensive review of the physical/chemistry properties, fate and transport, human and ecological health effects, and occurrence of coal tar creosote.