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 such as polycyclic
aromatic hydrocarbons (known as PAHs),
phenol,
cresols created by high temperature treatment of
beech and other woods,
coal, or from the
resin of the
Creosote bush. See also
preservative.
Wood creosote is a colorless to yellowish greasy liquid with a smoky odor and burned taste.
Wood creosote has been used as a
disinfectant, a
laxative, and a
cough treatment[
1], but these have mostly been replaced by newer medicines.
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.
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. Virtually all wooden
railroad ties and
telephone poles in use are treated with creosote to retard rotting. Coal tar, coal tar pitch (
pitch), and coal tar pitch volatiles are used for roofing,
aluminum smelting, and
coking.
Eating food or drinking water contaminated with high levels of creosotes may cause a burning in the mouth and throat, and stomach pains.
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.
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
EPA has determined that coal tar creosote is a probable human carcinogen.
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. It is unknown 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 no similar studies have been performed on 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.
In 2003 the European Union banned creosote for amateur and unlicenced professional use, due to concerns over these health effects, noting that recent research had shown that the risk of skin cancer had perhaps been underestimated previously.
*
Creosote factsheet from the
UK Department of Trade and Industry*
ATSDR creosote faq*
Tests of Creosoted Timber, Transactions of the
American Society of Civil Engineers, vol. LXX, Dec. 1910, by W. B. Gregory, from
Project Gutenberg
