Tobacco companies were aware of the dangers of a radioactive substance in cigarettes as early as 1959, but hid this knowledge from the public, according to a new study.
The substance, called polonium-210, causes cancerous growths in the lungs of smokers, according to ABC News. Scientists from the University of California, Los Angeles, studied 27 documents that had never been analyzed, and found tobacco companies calculated how much radiation a regular smoker would be exposed to over 20 years.
Lead researcher Hrayr Karagueuzian found the levels of radiation in cigarettes were responsible for up to 138 deaths for every 1,000 smokers over 25 years. The findings appear online in Nicotine and Tobacco Research.
Tobacco products still contain polonium. “The evidence of lung cancer risk caused by cigarette smoke radioactivity is compelling enough to warrant its removal,” the researchers wrote.
A process called “acid washing,” discovered in 1980, removes up to 99 percent of polonium-210 from tobacco. The documents show tobacco companies knew about acid washing but declined to use it. Although their official reasons for not using the technique were costs and environmental concerns, the documents show the process would change the nicotine in tobacco plants, making it less able to deliver an instant “nicotine kick” sensation.