Coal tar

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Coal tar is a brown or black liquid of high viscosity, which smells of naphthalene and aromatic hydrocarbons. 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. ^[1]

1 Applications
2 Safety
3 See also
4 References
5 External links

[edit] Applications

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.

It can be used in medicated shampoo, soap and ointment, as a treatment for dandruff and psoriasis, as well as being used to kill and repel head lice. When used as a medication in the U.S., coal tar preparations are considered an OTC (over-the-counter drug) pharmaceutical and are subject to regulation by the United States Food and Drug Administration. Name brands include Balnetar, Psoriasin, and Tegrin.

Coal tar was formerly used as one of the primary ingredients of asphalt pavements. Today, petroleum derived binders and sealers are most commonly used. These sealers are used to extend the life and lower maintenance cost associated with asphalt pavements, primarily in asphalt road paving, parking lots and walkways.

[edit] Safety

According to the International Agency for Research on Cancer, preparations that include more than 5 percent of crude coal tar are Group 1 carcinogen.

According to the National Psoriasis Foundation and the FDA, coal tar is a valuable, safe and inexpensive treatment option for millions of people with psoriasis and other scalp conditions. ^[2] Coal tar concentrations between 0.5% and 5% are safe and effective for psoriasis and that no scientific evidence suggests that the coal tar in the concentrations seen in non-prescription treatments is carcinogenic. The NPF states that coal tar contains approximately 10,000 different chemicals, of which only about 50% have been identified ^[3], and the composition of coal tar varies with its origin and type of coal (eg: lignite, bituminous or anthracite) used to make it.