Properties and Health Effects

Summary
Creosote is a mixture of many chemicals. Eating food or drinking water with high levels of creosote may cause burning in the mouth and throat, and stomach pain. Long-term contact with creosote has been associated with increased risk of contracting cancer.

What is creosote?
Creosote is the name used for a variety of products: wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles. These products are mixtures of many chemicals created by burning of beech and other woods, coal, or from the resin of the creosote bush. Wood creosote is a colorless to yellowish greasy liquid with a smoky odor and burned taste. Coal tar creosote is a thick, oily liquid typically amber to black in color. Coal tar and coal tar pitch are usually thick, black, or dark-brown liquids or semi-solids, with a smoky odor. Wood creosote has been used as a disinfectant, a laxative, and a cough treatment, but has since been replaced by better medicines. Coal tar products are used in medicines to treat skin diseases such as psoriasis, and also as animal and bird repellents, insecticides, animal dips, and fungicides. Coal tar creosote is the most widely used wood preservative in the United States. Coal tar, coal tar pitch, and coal tar pitch volatiles are used for roofing, aluminum smelting, and coking.

What happens to creosote when it enters the environment?
Coal tar creosote is released to water and soil mainly as a result of its use in the wood preservation industry. Components of creosote that do not dissolve in water will remain in place in a tar-like mass. Some components of coal tar creosote dissolve in water and may move through the soil to groundwater. Once in groundwater, it may take years for it to break down. Coal tar creosote can build up in plants and animals. We do not know what happens to wood creosote when it enters the environment.

How might I be exposed to creosote?
Using products that contain creosote to improve skin problems such as eczema or psoriasis. Eating herbal remedies containing the leaves from the creosote bush, which are sold as dietary supplements. Working in the wood preservative, coke-producing, or asphalt industries. Using creosote-treated wood in building fences, bridges, or railroad tracks, or installing telephone poles. Living in treated-wood houses that may result in air or skin contact with creosote. Drinking water contaminated by a hazardous waste site.

How can creosote affect my health?
Eating food or drinking water contaminated with high levels of creosotes may cause a burning in the mouth and throat, and stomach pains. Taking large amounts of herbal remedies containing creosote bush leaves may cause damage to the liver or kidney. Brief direct contact with large amounts of coal tar creosote may result in a rash or severe irritation of the skin, chemical burns of the surfaces of the eyes, convulsions and mental confusion, kidney or liver problems, unconsciousness, and even death. Longer direct skin contact with low levels of creosote mixtures or their vapors can result in increased light sensitivity, damage to the cornea, and skin damage. Longer exposure to creosote vapors can cause irritation of the respiratory tract.

How likely is creosote to cause cancer?
Long-term exposure to low levels of creosote, especially direct contact with the skin during wood treatment or
manufacture of coal tar creosote-treated products, has resulted in skin cancer and cancer of the scrotum. Cancer of the scrotum in chimney sweeps has been associated with long-term skin exposure to soot and coal tar creosotes. Animal studies have also shown skin cancer from skin exposure to coal tar products. The International Agency for Research on Cancer (IARC) has determined that coal tar is carcinogenic to humans and that creosote is probably carcinogenic to humans. The U.S. EPA has determined that coal tar creosote is a probable human carcinogen.

How can creosote affect children?
There is no unique exposure pathway of children to creosote. Children exposed to creosote will probably experience the same health effects seen in adults exposed to creosote. Children who played on soil contaminated with creosote had more skin rashes than children who played in uncontaminated areas. We do not know whether children differ from adults in their susceptibility to health effects from creosote. Studies in animals have shown birth defects in the young of mothers exposed to high levels of creosote during pregnancy, but we do not know whether the same effects would occur in humans. Some animal studies indicate that creosotes may cross the placenta and reach the fetus. Because chemical components (PAHs, cresol, phenols) of coal tar creosote may be stored in body fat, they may be found in breast milk and could pass to nursing infants.

How can families reduce the risk of exposure to creosote?
If you live in a residential area that used to have a wood preservation facility or gas manufacturing plant nearby, wear long-sleeved shirts and long pants when working or playing outside and avoid using water contaminated with creosote. Instruct children not to come in contact with creosote-treated wood when playing on or near railroad tracks, in ditches close to utility poles, in old barns or other farm structures, or on bridges or piers. Avoid using herbal remedies containing the leaves of the creosote bush and seek alternatives to skin remedies containing creosote. If you are exposed to creosote in the workplace, make sure you do not carry the chemical home in your clothing, skin, hair, tools, or other objects from the workplace (shower before going home).

Is there a medical test to show whether I’ve been exposed to creosote?
There is no medical test to determine if you have been exposed to creosote. Some components of creosote mixtures can be measured in body tissues, urine, or blood after exposure to creosote. These tests cannot tell whether harmful health effects will occur. The tests are not routinely available at the doctor’s office because they require special equipment.

Has the federal government made recommendations to protect human health?
The Occupational Safety and Health Administration (OSHA) has set an exposure limit of 0.2 milligrams of coal tar pitch volatiles per cubic meter of air (0.2 mg/m3) in workplace air during an 8-hour day, 40-hour workweek.

References
Agency for Toxic Substances and Disease Registry (ATSDR). 2002. Toxicological Profile for Creosote (Update).
Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Updated: September 2002