Radon - the killer in tobacco
Out of the nearly 4,000 chemicals found in tobacco smoke, only two definite
chemical carcinogens have been found - benzopyrine and nitrosamine.
However, the most potent carcinogen in tobacco is radiation from the
radioactive products of radon. Polonium-210 is the only component of
cigarette smoke that has produced cancers by itself in laboratory animals
by inhalation - tumors appear at a level five times lower than the
dose to a heavy smoker.
Lung cancer rates among men kept climbing from a rarity in 1930 (4/100,000
per year) to the No. 1 cancer killer in 1980 (72/100,000) in spite of
an almost 20 percent reduction in smoking. But during the same period,
the level of polonium-210 in American tobacco had tripled. This coincided
with the increase in the use of phosphate fertilizers by tobacco growers
- calcium phosphate ore accumulates uranium and slowly releases radon
As radon decays, its electrically charged daughter products attach themselves
to dust particles, which adhere to the sticky hairs on the underside
of tobacco leaves. This leaves a deposit of radioactive polonium and
lead on the leaves. Then, the intense localized heat in the burning tip
of a cigarette volatilizes the radioactive metals. While cigarette filters
can trap chemical carcinogens, they are ineffective against radioactive
The lungs of a chronic smoker end up with a radioactive lining in a
concentration much higher than from residential radon. These particles
emit radiation. Smoking two packs of cigarettes a day imparts a radiation
dose by alpha particles of about 1,300 millirem per year. (IEM) For comparison,
the annual radiation dose to the average American from inhaled radon
is 200 mrem. However, the radiation dose at the radon "action level" of
4 pCi/L is roughly equivalent to smoking 10 cigarettes a day.
Philip Morris scientists wondered how come that the heavy tobacco users
in the Caucasus live remarkably long lives. The local tobacco growers
do not use phosphate fertilizers. But the American smoker inhales on
average about 0.04 pCi of polonium-210 per cigarette, which disgorges
alpha particles. It has a half life of only 138 days, making it thousand
times more radioactive than the nuclear fuel used in the Hiroshima bomb.
Polunium-210 is soluble and is circulated through the body to every
tissue and cell in levels much higher than from residential radon. The
proof is that it can be found in the blood and urine of smokers. The
circulating polonium-210 causes genetic damage and early death from diseases
reminiscent of early radiological pioneers: liver and bladder cancers,
stomach ulcers, leukemias, cirrhosis of liver, and cardiovascular diseases.
The Center for Disease Control concluded "Americans are exposed
to far more radiation from tobacco smoke than from any other source." The
Surgeon General C. Everett Koop stated that radioactivity, rather than
tar, accounts for at least 90% of all smoking-related lung cancers.
Cigarette smoking accounts for 30% of all cancer deaths. Only poor diet
rivals tobacco smoke as a cause of cancer in the U.S., causing a comparable
number of fatalities each year. However, the National Cancer Institute,
with an annual budget of $500 million, has no active funding for research
of radiation from smoking or residential radon as a cause of lung cancer,
presumably, to protect the public from "undue fears of radiation."
Dr. Gordon Edwards: Estimating Lung Cancers
Radioactive Polonium in Tobacco, Meat and Dairy