Tobacco manufacturers discovered over 40 years ago that radioactive polonium-210 [3] exists in cigarettes and tobacco smoke, and spent decades working to remove it, according to a new study [4] published in the American Journal of Public Health [5]. The companies tried to remove polonium -- a naturally-occurring, alpha particle-emitting constituent of the fertilizers and soil used to grow tobacco -- by creating special filters, washing the tobacco leaf and genetically altering tobacco plants, but ultimately failed. Instead of coming clean, the companies kept their internal research on polonium and information about their unsuccessful efforts to remove it secret. They didn't want to heighten public awareness of polonium in cigarettes. Polonium-210 is the lethal radioactive substance that was used to poison Russian dissident Alexander Litvinenko [6] in London in 2006.