Coal tar

Coal tar is a brown or black liquid of extremely high viscosity. Coal tar is among the by-products when coal is carbonized to make coke or gasified to make coal gas. Coal tars are complex and variable mixtures of phenols, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic compounds.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.

Uses

Pavement sealcoat

Coal tar is incorporated into some parking-lot sealcoat products, which are used to protect and beautify the underlying pavement. Sealcoat products that are coal-tar based typically contain 20 to 35 percent coal-tar pitch. Research shows it is used in United States states from Alaska to Florida and several areas have banned its use in sealcoat products including: The District of Columbia; the City of Austin, Texas; Dane County, Wisconsin; Washington State; and several municipalities in Minnesota and others.

Industrial

Being flammable, coal tar is sometimes used for heating or to fire boilers. Like most heavy oils, it must be heated before it will flow easily.