According to the World Health Organization, radon is much more likely to cause lung cancer in people who smoke. In fact, smokers are estimated to be 25 times more at risk from radon than non-smokers [Note: this is increased from previous EPA estimates of 20 times more risk]. In addition to naturally occurring radon in the home, cigarettes are also a contributor to radon-induced lung cancer. It is widely assumed that the 69 known carcinogens in cigarettes are to blame for smoker-related lung cancers. However, U.S. grown tobacco products contribute significantly to radiation exposure, often in lethal doses.
The tobacco leaves used in making cigarettes contain radioactive material, particularly lead-210 and polonium-210. Phosphate fertilizers are used for flavor enhancement and contain radium and its decay products (including lead-210 and polonium-210). When phosphate fertilizer is spread on tobacco fields year after year, the concentration of lead-210 and polonium-210 in the soil rises. The radionuclide content of tobacco leaves depends heavily on soil conditions and fertilizer use. RDPs cling to dust particles that are collected by the sticky tobacco leaves. The sticky compound that seeps from the trichomes is not water soluble, so the particles do not wash off in the rain. They stay through curing and cutting process, and are manufactured into cigarettes. More than 40 years ago, the major US tobacco manufacturers acknowledged that polonium, the “mother source” of radon, was part of tobacco and tobacco smoke. They attempted, but failed, to remove the radioactive substance from their products. Internal tobacco industry documents reveal that the companies suppressed publication of their own internal research to avoid heightening the public’s awareness of radioactivity in cigarettes. Tobacco companies continue to minimize their knowledge about polonium-210 in cigarettes in smoking and health litigation. Physicians and researchers from the American Journal of Public Health propose that radiation-exposure warning labels be printed on cigarette packs. [Ref. 2]
Knowledge of radiation contamination was first disclosed by in 1968 when high levels of PO-210 were verfied in various cigarette brands. After this confirmation, some tobacco manufacturers sought to remove PO-210 from its products but ultimately failed to substantially reduce its concentration in the tobacco leaf. Tobacco company scientists confirmed that decontamination efforts yielded a 10%-40% reduction in leaf radioactivity. However, in 2001 former Philip Morris scientist William Farone testified during subsequent litigation that the manufacturers opted to cease the efforts to lower PO-210 levels due to the “disadvantages with respect to economics and loss in flavorants which outweigh the advantages of marginally reduced biological activity for this type of process.”
|Radiation Equivalency of Cigarettes |
1 ½ Packs a day = 300 Chest X-Rays
According to the U.S. Division of Radiation Safety, cigarette smoke contains an amount of radioactive lead and polonium powerful enough to result in a radiation exposure of 1600 mrem/year to a 1.5 pack a day smoker. A modern chest X-ray is about 8 mrem, and a cigarette is about 1.5 mrem, which is the equivalent to one chest x-ray per 5 cigarettes smoked. Most disturbing, a non-smoker living with a smoker may receive the equivalent of 12 chest x-rays per year as a result of second-hand smoke. Due to the concentration of carcinogens in cigarettes, secondhand smoke contains over 4,000 chemical compounds, including 69 known carcinogens such as formaldehyde, lead, arsenic, benzene, and of course radioactive PO- 210.
The chart in Figure 1-6 shows the radiation dose of cigarettes in comparison with other sources. Note the exposure of tobacco products versus that of a chest x-ray. According to the National Institutes of Health, in a person smoking 1.5 packs of cigarettes per day, the radiation dose is the equivalent of the dose to the skin from 300 x-ray films of the chest per year.