View source for Coal tar

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==Overview==
'''Coal tar''' is a brown or black liquid of high [[viscosity]], which smells of [[naphthalene]] and [[aromatic hydrocarbon]]s. Coal tar is among the by-products when coal is carbonized to make [[coke (fuel)|coke]] or gasified to make coal gas. Coal tars are complex and variable mixtures of [[phenols]], [[polycyclic aromatic hydrocarbon]]s (PAHs), and [[heterocyclic compound]]s. <ref name="c">[http://www.atsdr.cdc.gov/toxprofiles/tp85-c2.pdf TOXICOLOGICAL PROFILE FOR WOOD CREOSOTE, COAL TAR CREOSOTE, COAL TAR, COAL TAR PITCH, AND COAL TAR PITCH VOLATILES] U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, page 19, [[September 2002]]</ref>

==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 [[United States|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.

==Safety==
According to the [[International Agency for Research on Cancer]], preparations that include more than 5 percent of crude coal tar are [[List of IARC Group 1 carcinogens|Group 1]] [[carcinogen]]. 

Despite this, the National Psoriasis Foundation claims coal tar is a valuable, safe and inexpensive treatment option for millions of people with psoriasis and other scalp conditions, <ref>National Psoriasis Foundation, [http://www.psoriasis.org/news/stories/2001/20011202_coalcala.php The battle to save coal tar in California], Dec 3 2001.</ref> the FDA agrees with this and states that 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 <ref>http://www.psoriasis.org/treatment/psoriasis/topicals/tar.php</ref>, and the composition of coal tar varies with its origin and type of coal (eg: [[lignite]], bituminous or [[anthracite]]) used to make it, so much further research remains to be done on coal tar and its derivatives.

==See also==
* [[Creosote]]
* [[Cresolene]]
* [[Preservative]]
* [[Tar]]

==References==
{{reflist|1}}

[[Category:Coal]]
[[Category:Dermatological preparations]]
[[Category:Materials]]
[[Category:IARC Group 1 carcinogens]]
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