FRIDAY, Sept. 30, 2011 (HealthDay News) -- A new study claims that tobacco companies knew for years that cigarette smoke contained dangerous and potentially deadly radioactivity but purposefully didn't let the public know.
A representative of one of the tobacco companies, however, said it is "illogical" to say that the existence of the radioactivity was secret or covered up.
The study authors said that their analysis of internal tobacco industry documents shows company researchers long knew about the risk of radioactivity and began investigating its health risk some five decades ago.
The risk comes from the isotope polonium-210, which emits radiation and can be found in all commercially available domestic and foreign cigarette brands, the study's first author, Hrayr S. Karagueuzian, a professor of cardiology at the University of California, Los Angeles Cardiovascular Research Laboratory, said in a news release provided by the university.
"The documents show that the industry was well aware of the presence of a radioactive substance in tobacco as early as 1959," the study authors wrote. "Furthermore, the industry was not only cognizant of the potential 'cancerous growth' in the lungs of regular smokers, but also did quantitative radiobiological calculations to estimate the long-term lung radiation absorption dose of ionizing alpha particles emitted from cigarette smoke."
"They knew that the cigarette smoke was radioactive way back then and that it could potentially result in cancer, and they deliberately kept that information under wraps," Karagueuzian said. "Specifically, we show here that the industry used misleading statements to obfuscate the hazard of ionizing alpha particles to the lungs of smokers and, more importantly, banned any and all publication on tobacco smoke radioactivity."
The study noted that the tobacco industry also declined to do things that could have helped rid their products of polonium-210.
The researchers said they came to their conclusions after reviewing documents from Philip Morris; R.J. Reynolds; Lorillard, Brown & Williamson; the American Tobacco Company; The Tobacco Institute; and the Council for Tobacco Research, among others.
Representatives of several of the tobacco companies didn't return messages seeking comment. A spokeswoman for British American Tobacco (which bought American Tobacco Company and previously owned Brown & Williamson) debunked the study's claims in an interview.
"Scientific studies into radioactive substances in tobacco began in the 1950s and continued since that time," said the spokeswoman, Marina Murphy. "From the 1950s to 1990, over 100 papers had been published investigating the radioactivity present in tobacco and tobacco smoke, with the majority of these focused on polonium-210. It is therefore illogical to claim that the presence of polonium-210 in tobacco has been covered up or is a secret."
The new study was released online this week in advance of publication in an upcoming print issue of the journal Nicotine & Tobacco Research.
The U.S. National Library of Medicine has more on smoking.