For more than four decades, the tobacco companies knew about the cancer risk posed by radioactive isotopes in smoke, But concealed ...deliberately data, concludes new research by the University of California at Los Angeles. examining internal documents of the industry, which released in 1998 in an out of court settlement, the researchers showed that the companies knew since 1959 about the existence of radioactive polonium-210, an isotope that occurs naturally in soil and fertilizers. "knew that cigarette smoke is radioactive and can potentially lead to cancer, but deliberately kept this information secret," says Chrair Karagkouzian, Professor of Cardiology and member of the research team. The findings are published in the journal Nicotine and Tobacco Research. worried about the effects of polonium-210, the tobacco companies started to study in depth the issue after 1960. The internal company documents even allowed the researchers to assess the risk for smokers was estimated as the time companies: 120 to 138 extra deaths per 1,000 smokers by 25 years. polonium-210 accumulate in "hot spots" in the bronchi of smokers instead spreads evenly over the surface. There, decays by emitting alpha particles, ie hydrogen nuclei, which can cause genetic damage in other cells. And the bombardment of cells with a particle is added to the carcinogenic effects of benzene and other toxic substances in tobacco. Previous studies in dead smokers had indeed shown that the tumors usually appear in these "hot spots." Despite indications cancer risk, says new study, tobacco companies have refused to adopt methods for the removal of polonium-210 in tobacco. The newest of these techniques, discovered in 1980, tobacco washes with acids. "The industry was concerned that the acidic medium will cause ionization of nicotine, making it more difficult for absorption in the brains of smokers," wrote the researchers.
