A tobacco researcher is calling for the U.S. Food and Drug Administration to consider making the removal of cancer-causing radioactive particles from tobacco products a top priority.

“Such a move could have a considerable public health impact, due to the public’s graphic perception of radiation hazards,” said UCLA researcher Hrayr S. Karagueuzian in a statement released Tuesday.

The call comes after the release of a report in the journal Nicotine and Tobacco Research by Karagueuzian and colleagues which says tobacco companies identified a radioactive substance in cigarettes in the 1960s and kept knowledge of its existence from the public for over four decades.

The information comes from documents provided by the tobacco industry as part of a 1998 settlement with nearly all U.S. states over healthcare costs linked to tobacco use.

The industry was aware of the presence of a radioactive substance as early as 1959, the researchers said.

“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,” wrote the authors of the study.

Karagueuzian, a cardiology professor at UCLA said “the industry used misleading statements to obcuscate the hazard … and more importantly banned any and all publication on tobacco smoke radioactivity.”

The substance, polonium-210, is found in all commercially available domestic and foreign cigarette brands, Karaguezian said.

The substance is absorbed by the leaves through naturally occurring radon gas in the atmosphere and through fertilizers.

Researchers said one tobacco industry study nearly 25 years ago measured the potential lung burden from radiation exposure in a two-pack-a-day smoker over a two-decade period.

The levels or radiation absorbed by regular smokers over a 20 or 25 year period “equaled 40 to 50 rads,” Karagueuzian said.

“These levels of rads, according to the EPA's (Environmental Protection Agency) estimate of lung cancer risk in residents exposed to radon gas, equal 120 to 138 deaths per 1,000 regular smokers over a 25-year period," he said.

An “acid-wash” technique to remove the radioactive isotope from tobacco plants was known to the industry, Karagueuzian said.

While the industry cited concerns over the cost and potential environmental impact of the technique as rationales for not using it, researchers said the reason may have been different.

"The industry was concerned that the acid media would ionize the nicotine, making it more difficult to be absorbed into the brains of smokers and depriving them of that instant nicotine rush that fuels their addiction," Karagueuzian said.