Reuters Health - - - The tobacco industry for many years claimed that it was unaware of biological evidence that smoking is harmful to health. However, documents made public as a result of a 1998 legal settlement show that Philip Morris sponsored secret research that revealed tobacco's addictive properties and the toxicity of sidestream smoke, according to a report in The Lancet, to be published online on November 11th.
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In the 1980s, animal experiments conducted by INBIFO demonstrated high levels of toxicity from sidestream smoke. Dr. Diethelm's team traced "more than 800 scientific reports dealing with sidestream smoke undertaken by INBIFO between 1981 and 1989." However, they add, it was not until 1994 that researchers at INBIFO published research concerning sidestream smoke.
Papers published in scientific journals during this time "appear to be of considerable value to the industry," Dr. Diethelm's team notes, "casting doubt upon the value of markers of passive smoking and suggesting alternative explanations for the observed epidemiological association between passive smoking and lung cancer."
http://www.medscape.com/viewarticle/493519?src=mp