Tobacco companies will be required to report on a range of toxic chemical ingredients found in its products, the Associated Press reported.
U.S. News and World Report said the preliminary guidance issued Friday by the Food and Drug Administration marks the first time the industry will have to list quantities of 20 different ingredients associated with cancer, lung disease and other health problems on consumer-friendly packaging by April 2013.
"For the first time, all tobacco manufacturers will be required to report quantities of potential harmful compounds in every regulated tobacco product they sell in the U.S.," said Dr. Lawrence Deyton, director of FDA's Center for Tobacco Products.
"Cigarettes are the only mass-consumed product in this country for which consumers don't know what's in them, until now," he told the AP.
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There are more than 7,000 chemicals in tobacco and tobacco smoke.
Regulators have identified more than 93 chemicals and are focusing on 20 that are harmful including ammonia, carbon monoxide and formaldehyde.
A 2009 law authorized the FDA to regulate a number of aspects of tobacco marketing and manufacturing, though it cannot ban nicotine.